Laptop Computer Repair Welcome Guest | Login or Register

It is extremely important not to make or write any changes to data on the hard drive without first verifying the hard drive configuration. Therefore, the first priority when unable to access information on a hard drive is to verify all of the configuration information dealing with the suspect hard drive.

Partition Parameter

Value or Equation

Partition Status

Bootable

Starting Head

1

Starting Sector

1

Starting Cylinder

0

Partition Type

Bigdos (drives greater than 30 MB), otherwise DOS 12

Ending Head

Total Number of Heads -1

Ending Sector

Sectors per Track displayed in Volume Boot Sector

Ending Cylinder

Number of Cylinders set in CMOS - 2

Total # of Sectors

Number of Sectors displayed in Volume Boot Sector

Start Absolute Sector

Number of Sectors per Track in Volume Boot Sector

Boot Signature

55AA

Step One: Make sure that Micro-Scope detects the hard drive

In Micro-Scope, System Configuration, Compare Settings - check to make sure that there is not an asterisk beside the number of hard drives detected value. If there is an asterisk, either the CMOS is set incorrectly, or there is an electronic problem (controller, cable, drive).

Step Two: Compare the BIOS parameters against the drive partition information.

In Micro-Scope, System Configuration, System Information - note the information displayed for the hard drive, specifically the parameters for the drive in question. Compare these parameters to the parameters in the MBR display under Micro-Scope, System Configuration, Partition Display using the following formula:

System Information

Master Boot Record

Cylinders

Ending Cylinder + 2

Heads

Ending Head + 1

Sectors

Sectors Per Track

If the information does not match, either the partition information is corrupt, or the CMOS setup or controller BIOS setup (if one exists) is incorrect, or there is a problem communicating with the drive.

Step Three: Check the drive functionality

In Micro-Scope, Diagnostics, Fixed Disk Tests - check the information in the Fixed Disk Selected window. Make sure that the proper drive type, model, and native parameters are showing in this window. If any of the information is incorrect, there is an electronic problem. Check the cable, controller and drive, re-seating all connections, and repeat the above procedure. After correcting the electronic problem, perform a read test on the first 10 cylinders of the drive. If any errors occur, then this is the most likely cause of the drive failure. Perform a read of the entire drive to determine if the errors are electronic in nature, or physical in nature. Electronic problems will result in the errors displayed not always being the same type or in the same location on the drive. If the problem is electronic, replace the cable, controller, and finally drive electronics and repeat the read test until no errors occur. If the error is physical, use an INT 13 type editor (such as Norton Advanced Editor), to block the entire drive and write the information to a daisy chained drive set to the same parameters as the faulty drive.

The next step, after the drive passes the read test on the first 10 cylinders, is to check the original partition setup of the drive.

Step Four: Check for the physical location of the master boot sector and the volume boot sector.

In Micro-Scope, Utilities, Fixed Disk Editor - use the FIND feature to search the last two bytes of each cylinder for a boot signature (55 AA). The first location where a boot signature should be found would be at cylinder 0, head 0, sector 1 (the master boot sector). The second location where a boot signature should be found is at cylinder 0, head 1, sector 1 (the volume boot sector). It is also possible to use the FIND feature to locate the volume boot sector by searching for MSDOS (in DOS based systems) or MSWIN (in Windows95 systems).

If there is a duplicate copy of the master boot sector found before the location of the volume boot sector, then it is possible that a boot virus has infected the hard drive in the system. The Rebuild Master Boot feature of Micro-Scope will eliminate any boot sector virus. Be sure to boot the system to the Micro-Scope diskette and immediately do a cold reboot of the system after using the Rebuild Master Boot feature.

If the volume boot sector is found in a location other than cylinder 0, head 1, sector 1, count the actual number of sectors before the volume boot sector, and compare that value to the value for the sectors per track displayed in the partition table described in step 2. If the values match, the most likely cause of the system failure is an incorrect CMOS setup. In this case the CMOS needs to be reset to the values indicated by the partition table described in step 2, remembering to use the formula described in step 2 when doing so. If the values do not match, set the CMOS Sectors Per track to the number of sectors counted before the volume boot sector and continue to the next step.

Step Five: Check the partition tables to make sure they are correct

Reboot the system to Micro-Scope and go to System Configuration, Partition Tables. Check the information displayed in the master boot record to see if there is any obvious corruption (that is, excessively large numbers, all partitions non-bootable, etc.) If there is no obvious corruption in the master boot record, then perform step 2 again. If the information matches at this point, go to step 6. If the information does not match, then set the sectors per track in the Master Boot Record to the number of sectors per track currently set in CMOS, set the starting head to 1, starting sector to 1, and starting cylinder to 0, and write the information to the drive.

Step Six: Verify the Master Boot Sector information

Display the Volume Boot Sector and use the values for heads and sectors per track (on the right half of the screen) to perform step 2 again.

If the values match, then the volume boot sector is probably okay. If any values in the Master Boot Record do not match the table to the right, reset the values to match the values in the table, and write to the drive.

If the values still do not match, both the Master Boot Record and the Volume Boot Record are probably corrupt. At this point, e-mail Technical Support for help in this situation. Future articles will provide more insight into the repair procedure.

Step Seven: Check the FATs

Check to see if the first FAT starts on the sector just beyond the volume boot sector. Use the find feature in the Fixed Disk Editor to search for F8 FF FF in the first three bytes of each sector. The first occurrence should be on sector two of head one. Continue to search until the second FAT is found, indicated by the second occurrence of F8 FF FF. Note the location of the cylinder, head and sector of the second FAT.

Based on the start of the second FAT, and the start of the first FAT, calculate how many sectors are in the first FAT. If necessary, read each sector starting at the first sector of the first FAT, keeping a count of the sectors that have been read until F8 FF FF is seen in the upper left of the HEX display, which would indicate the start of the second FAT. After calculating the sectors per FAT, compare this value to the value in the volume boot sector. If the values match, the drive should be accessible through DOS at this point.

Step Eight: Attempt to access the drive

Boot to a DOS-bootable floppy diskette and attempt to access the drive. If the root directory and sub-directories on the hard drive are readable at this point, then attempt to boot to the drive. If the drive boots at this point, the problem has been corrected. If the drive is still not bootable, e-mail the Micro 2000 Technical Support department for help.

Disclaimer - The Micro 2000 Tech Tip is a free service providing information only. While we use reasonable care to see that this information is correct, we do not guarantee it for accuracy, completeness or fitness for a particular purpose. Micro 2000, Inc. shall not be liable for damages of any kind in connection with the use or misuse of this information.

Micro 2000 Inc has been helping to solve the day-to-day challenges that IT departments face in order to keep their businesses operational as well as profitable for over 14 years. The company’s primary goal is to put the customer first - through feature-rich, simple-to-use IT tools that can help IT administrators manage their jobs more effectively.

For more advice and free articles be sure to visit: http://www.micro2000.co.uk

Tags: computer, diagnostics, hard drives, maintaining pcs and computers, PC, pc and computer tools, tech tipscomputer, diagnostics, hard drives, maintaining pcs and computers, PC, pc and computer tools, tech tips

Share This

If the system still does not boot after the above, try to boot in ‘Safe Mode’ Restart, and use the F8 key as before. This time select ‘Safe Mode’ and hit Enter. The screen displays a list of drivers and then continues with the boot process.

If you arrive at the basic desktop, the boot has gone OK. ‘Safe Mode’ will be indicated in each corner of the screen, and the icons will probably appear larger than normal. This is because only a basic video driver is being used, instead of your high speed video card!

Having successfully booted, we can assume that the problem was with one of the drivers which were left out due to Safe Mode. You should be able to determine which driver is causing the problem.

What was the last action you performed? Maybe you downloaded an update for your video card, and selected the wrong version! In this case you can go to Device Manager (Start - Control Panel - System - Hardware Tab - Device Manager).

In this example of the Video Card Driver, expand Display Adapters, right click on your device and select Properties. Under the Driver tab select Rollback Driver.

This will replace the driver with the previous version. You will now need to reboot by following the prompts, and your system should now operate as before.

For other drivers, the procedure is the same.

If you can boot in safe mode, but can’t resolve a the problem further, or if you still have stability problems, go to the next step.

If you have recently installed software, even if you have removed it again, it is worth performing a System Restore.

‘System Restore’ is a function introduced in Windows Millenium Edition, or ME (possibly the only good point!) In windows XP it is more automated, in that many updates and installs set a ‘restore point’ before installing.

The restore point is a snapshot of various system registers etc., which can be re-instated if a problem with the system occurs.

The restore point can be set manually by the user, for example before installing or updating software, go to the Help Center as described below.

To invoke System Restore go to Start - Help and Support - System Restore. (To set a restore point choose Create a restore point).

Select ‘Restore my Computer to an Earlier Time’. Next you are shown a calendar with the dates of recent restore points highlighted. Selecting one of these, displays a note of what points are available.

Choose the latest time when you know your system was operating correctly, then click Next. Follow the instructions and the restore will proceed. After the system reboots, you system should be back to normal.

Tony is an experienced computer engineer. He is currently webmaster and contributor to http://www.what-why-wisdom.com . These articles may be seen at http://www.what-why-wisdom.com/computertroubleshooting-2.html . RSS feed also available - use http://www.what-why-wisdom.com/Educational.xml

Tags: computer, PC, troubleshootingcomputer, PC, troubleshooting

Share This

There’re viruses that don’t affect human body but are still really painful for mankind. It is computer viruses. A computer virus itself is a program that diffuses into the computer files and cracks them. The first acknowledged virus dates back to 1987 called the “Brain”. The “Brain” is a boot sector virus. A boot sector virus affects the boot sector which is a small program where information about the drive or disk structure is held. The boot sector is used when the operating system is started up. As a result of the virus attaching itself to the boot sector, every time the computer boots up, the virus is loaded to memory. This type of virus can spread very quickly in environments where computers are shared. A boot sector virus works as long as the computer is on and this guarantees that the virus gets executed because all computers need to boot up. Other types of viruses are the file or program infector viruses, the macro viruses and most recently, e-mail viruses. The file or program viruses connect themselves to executable programs and then once the programs are run, they load themselves onto memory and from there infect the rest of the computer.

Macro viruses attack programs with macros, which are programs that allow users to run a single input and be able to trigger a series of instructions which the computer automatically executes. Macro viruses infect such programs as spreadsheet and word processing files. They are dangerous because once the file is shared the virus is also shared. Also, these viruses can be spread to different platforms such as from Microsoft Windows to Macintosh operating systems which make these viruses more harmful. More recently, e-mail viruses have become popular. Worms such as the “Melissa virus” have been a threat in recent years where the worm would affix itself to a Word Document and then the virus would create an email and send it to the first fifty people of the user’s e-mail address book. This caused such a widespread infection that it forced Microsoft and other companies to shut down their email systems for a while. There are also the Trojan viruses that disguise themselves behind something valid and useful and then they would infect files once the disguises are opened. Trojans do not reproduce like worms but it can destroy files and cause harm like them. The general public’s view of a virus writer is a misconception that he is a “dysfunctional, pasty-faced teenager with no girlfriend and no life”. One reason that can be attributed to this generalization is the fact that the internet is able to hide the virus writer’s identity so the general public will take on a false impression of the writer. The realistic scenario is that most virus writers are normal people with normal lifestyles and they often do not write codes for malicious purposes. Virus writers come from different age groups, backgrounds, and countries. Many of them write viruses for different purposes. Most of the teenage virus writers code viruses for the excitement and the challenge that it brings.

Additionally, writing a new virus gives the writers credibility and status among their peers. Aside from the benign intentions of teenage virus writers, harm can be caused when they forget to “think about the effect their actions will have on other people”. Most virus writers who were teenagers in the past have already grown out of the virus writing phase and consider virus writing an inferior type of coding. Since the unveiling of the internet to the public, anyone that has access to a computer and internet can now go on the web and search for virus source codes and put together a malicious program and send it off through the internet. Current virus coders who still continue to write viruses and post them (source codes, not executable virus programs) on the internet agree that they “intentionally create and distribute viruses” to harm others. They do note that posting of source codes will not prevent those that have destructive intentions from putting together the source codes into a program and sending it off. The source code writers argue that they should not be held responsible for their creations because the writing of the code does not cause any real harm, but the person who puts them into a program and sends it to others are the culprit. The writing of virus serves many purposes like enhancing a person’s knowledge of code and learning how a virus works. Learning about viruses is beneficial because it forces many companies to build better systems to prevent virus attacks.

Another view on virus writers is that they use viruses for harmful intentions. Those that are “motivated by financial gain” are likely to be working with internet companies in order to make a profit off their virus victims. Some of these companies are internet spammers who hire the best virus writers around the world to help them. These virus writers are writing viruses for the sole purpose of stealing personal information from the computers of the people they infect. There are those virus writers who do it to “claim territory, to make a mark in the internet that will be seen by many others”. These types of writers are motivated by the feeling of the global damages they cause by sending their virus through the internet. Virus writers who write their code to do harm are like other criminals around the world. They have damaging intentions and they should be punished. Those that have outgrown the virus writing phase will eventually be replaced by new virus writers. However, in the United States, lawmakers are attempting to keep up with the quick changing technology and the problems that come with it. Although distribution of a virus with a malicious intent is considered a federal crime, the sole act of writing or providing easy access to virus code is not. The United States courts have come to establish original computer code as a form of intellectual property, putting it in the same category as music and artwork. Intellectual property is protected under the 1st Amendment of free speech. This was established in 1995 after a graduate student, Daniel Bernstein, filed a law suit against the government for violating his constitutional right because to post an encryption program, the government ruled that he would need to register as an international weapons dealer fearing that the program would mask illegal activity. States have also attempted to coin their own laws but they are limited to addressing unauthorized access to networks or sabotage. This is because other computer laws they try to address come up against the roadblock of the extraterritoriality of the crimes. Therefore, the best legislation enacted so far is the CFAA. Viruses will most likely begin to enter newer territory. For example, the Phage virus, was the first virus to be written for handheld devices (PC world) and it is likely that it is just the beginning of many to come which can be spread through ‘beaming’ features of handheld devices. There is also a more menacing fear that malicious code will be used in cyber-terrorism, much like an electronic weapon of mass destruction, and many experts are surprised this still has not occurred seeing that most systems are not well equipped to deal with this kind of attack.

The article was produced by the member of masterpapers.com.
Sharon White has many years of a vast experience in Essay Writing and custom essays writing consulting. Get free samples of essays and courseworks and buy essays .

Tags: computer, Computer Viruses, e mail, internet, PCcomputer, Computer Viruses, e mail, internet, PC

Share This