Microsoft

Get IT Done: Give Windows 9x boot problems the boot

Learn the steps that help you pinpoint the causes of Windows 9x boot problems.


Supporting users on clients that use Windows 9x can present many challenges—often in the form of boot problems. Machines that worked fine yesterday can suddenly freeze up during the boot process, leaving you to figure out what changed on the operating system, or worse yet, what hardware component is no longer functioning. The following steps are designed to help you pinpoint the causes of Windows 9x boot problems.

Bootable floppy rescue-disk creation
The first step in investigating the boot problem is to obtain a bootable, floppy, rescue disk with a virus checker. (If you do not have a bootable, floppy, rescue disk, click here to learn how you can create one.) Boot from the floppy with the latest virus signature files for your particular virus-checking program, and check the user's hard drive for any viruses. Most virus-checking programs will automatically remove any viruses they find, but if they do not, they will either prompt you to remove the virus or simply list the locations of the viruses. If you do not find any viruses, you can move on to the next step.

Boot into Safe Mode
Next, boot into Windows using Safe Mode. When you first start the computer, tap the F8 key when you see the message “Windows is now starting.” You will see a list of one to eight options, depending on the configuration of the computer. Choose the Safe Mode option from the list (option three on most computers). If the computer boots to a desktop with a message box stating, “Windows is running in Safe Mode,” then the boot problem is either related to a device driver loading when Windows starts up, or Windows system files have become damaged. If the user recently changed a video driver or video settings, change the settings back to their previous state (click here for details). If you are able to boot into Windows normally after resetting the driver settings, then the video card does not support the settings or the driver that the user installed. If the user has not made any changes to the video or other drivers, then you will need to determine which files are not loading when Windows tries to boot by using the Logged option, as explained below.

Logging the problem driver
To determine which files are not being loaded into memory when Windows starts up, you need to press the F8 key when the computer beeps, just like before. Select the Logged option (option two on most computers) from the menu that pops up, and press Enter. When the computer boots, a file will be created that logs every attempt to load a driver, whether it was successful or not. If the computer still hangs at this point, reboot the computer again, and choose Safe Mode from the menu. When the dialog box pops up, click the OK button, open My Computer, and double-click the C drive. Search for a file called Bootlog.txt and open it in Notepad. Click the Search menu item in Notepad and click the Find option. In the Find What dialog box, type the word "fail" and click the Find Next button. The first driver that failed to load will be displayed and highlighted in the Notepad document. Write down the file names and locations of each driver that has failed.

From your list of failed drivers, you may notice a few files named Virtual device drivers. Virtual device drivers (VXDs) can be difficult and time-consuming to reinstall. The simplest solution is to back up your registry and run the Windows setup routine from the Windows installation CD. This will restore all the VXD files to their proper directories. While the registry will be overwritten with this procedure, you can simply replace the registry with the backup you made earlier. If you do not see any files listed as failed in the Bootlog file, then you may need to restore the registry.

Careful
Always proceed with caution when attempting to work with the registry. Any changes you make could have negative consequences on other parts of the operating system.

Restoring the registry
For Windows 95 systems, you can restore your registry in one of two ways. Your first option is to use the command line interface from a DOS prompt and follow the instructions in this Microsoft Knowledge Base article. If you do not feel comfortable using a command line interface, you can insert the Windows 95 CD and navigate to the Other\Misc\ERU folder. Run the Eru.exe file and follow the instructions on the screen. This option adds an extra benefit, because it not only backs up the registry files, but it also backs up all of the other system files, such as system.ini, win.ini, autoexec.bat, and config.sys. If the system does not have a backup copy of your registry, you will need to reinstall Windows from the Windows installation CD.

Windows 98 systems, however, automatically make a backup copy of the registry. The last time Windows loaded successfully with no errors, it backed up the system registry and startup files. To restore the registry in Windows 98, run the command Scanreg.exe from a DOS prompt. Choose the option to restore the registry from backup, and restart the computer. If the computer boots normally, you'll know that a recently changed software setting was the cause of the boot problem.

Reinstall Windows
If you've completed the steps above and the computer still will not boot properly, then system files may have been damaged. The only way to resolve this situation is to format the drive and reinstall Windows and all of the user's applications. For supporting multiple computers, I recommend using Ghost from Symantec. The program allows you to create an image for each model of computer you support, which will save you time when reinstalling Windows and all of the other applications on the user's computer.

Run Scandisk for a hard drive check
If you've come this far and the computer still locks up at the Windows splash screen, boot to a DOS prompt and run the Scandisk program. Scandisk will check your software for errors and check your hard drive for physical problems. When Scandisk finds sectors that are unreadable, it will mark them and try to copy the data to an area that has not been damaged. If several sectors are damaged (as identified in the Scandisk graphic display), the hard drive is susceptible to impending failure and should be replaced as soon as possible. When Scandisk completes, restart your computer. A successful boot indicates that Scandisk moved data from an unreadable area of the drive to an area that could be read by the operating system.

When all else fails, disable the cache
Have you ever booted up a computer and received an error message after the splash screen that says, "Windows protection error. Please reinstall Windows”? After reinstalling Windows, did you still receive the same error? I have done that a few times, and I decided to determine the cause of the problem. I knew this error had something to do with the memory installed in the motherboard, but after replacing the RAM did not resolve the problem, I figured the error was related to cache memory.

Since most computers do not have replaceable cache on their motherboards anymore, I take the following steps to determine if the culprit is the processor cache or motherboard cache. The first step is to get into the BIOS of the computer that is experiencing this problem. Every computer has a different key to press to enter the BIOS when the computer is booted up. Most computers use the Delete key or the F1 or F2 key. If you are unsure of which key to press, boot the computer and watch for a statement that will say something like, “Press (name of the key) to enter setup.” Once you have pressed the key, the BIOS screen will appear.

In most BIOS configurations, the settings will be in the BIOS Features screen. If the BIOS does not have a BIOS Features area, you will need to either consult the motherboard manufacturer's manual or search around in the BIOS for the CPU Internal Cache and the External Cache settings. Both of these settings should be set to Enabled.

From my experience, I have found that the Windows protection error mentioned above is due to a damaged CPU Internal Cache. Disable the CPU Internal Cache by following the instructions contained on your BIOS screen or motherboard manual, and save your changes when prompted as you leave the BIOS. Over 99 percent of the time, when the computer restarts, you will boot into Windows with no problems. But, if you still have problems, restart the computer again and re-enable the CPU Internal Cache and disable the External Cache in the BIOS. Exit the BIOS, and save the changes when prompted. When the computer restarts and you boot into Windows successfully, you will know you need to replace the motherboard to resolve the External Cache problem.

When things really go wrong, disable both caches
In extremely rare cases, you will need to disable both the CPU Internal Cache and External Cache. The computer will be functional with both the caches disabled, but at some point, you will need to replace both the CPU and the motherboard to get rid of the Windows protection error.

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