IMPORTANT: The following contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs.
This article describes how to perform clean-boot troubleshooting for Windows 98.>/p> For additional information about how to perform clean-boot troubleshooting for Windows Millennium Edition (Me), click the article number below to view the article in the Microsoft Knowledge Base: 267288 How to Perform a Clean Boot in Windows Millennium Edition

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft doesn't guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Clean-boot troubleshooting refers to methods of reducing behaviours that may occur because of your computer's environment. Many behaviours that occur when you run Windows or programs occur because there are conflicting drivers, terminate-and-stay-resident programs (TSRs), and other settings that are loaded when a computer starts. The computer's environment includes settings from the following files:

• Msdos.sys
• Config.sys
• Autoexec.bat
• Winboot.ini
• Windows\Winstart.bat
• Windows\System.ini
• Windows\Win.ini
• Windows\Wininit.ini
• Windows\System.dat
• Windows\User.dat

These files are loaded as part of the boot process when Windows starts, and the files help create the environment that is used by the operating system and programs.
You can use System Configuration Utility to create a backup copy of the startup files .
To do this, click Create Backup on the General tab in System Configuration Utility. You can choose to save the files in a folder on one of your hard disks, or you can save the files to a floppy disk, which is recommended.

1. Start the System Information tool, and then start System Configuration Utility:
   1. Click Start, point to Programs, point to Accessories,
   2. Point to System Tools, and then click System Information.
   3. On the Tools menu, click System Configuration Utility.
2. Start System Configuration Utility at the Run command. To do this,
   • Click Start, click Run, type msconfig.exe in the Open box, and then click OK.

To use System Configuration Utility to perform a clean boot follow these steps:

1. On the General tab, click Selective Startup, and then click to clear the following check boxes:
   • Process Config.sys File
   • Process Autoexec.bat File
   • Process Winstart.bat File (if available)
   • Process System.ini File
   • Process Win.ini File
   • Load Startup Group Items
2. Click OK, and then restart your computer when you are prompted to do so.

Each check box (except the Load Startup Group Items check box) represents files that are renamed with a troubleshoot (.tsh) file extension when you click to clear the check box.

• The Load Startup Group Items check box represents icons in the Startup folder or entries in the following registry keys: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
  -and-
  HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices When you click to clear the Load Startup Group Items check box, the registry entries are written in the following keys: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run-
  -and-
  HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices-
  -and-
  HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run- The icons in the Startup folder are moved to the Disabled Startup Items folder in the Windows\Start Menu\Programs folder.
• When you click to clear check box for a file, a "remark" statement is placed at the beginning of each line in the file.
  • For both the Config.sys and Autoexec.bat files, a "rem tshoot" statement followed by a space is placed at the beginning of the lines in the file for the check box that you click to clear.
  • For both the System.ini and Win.ini files, a "; tshoot" statement followed by a space is placed at the beginning of the lines in the file for the check box that you click to clear. These remarks are removed when you click to select a check box that you previously clicked to clear. When you click to select a check box for an item on the Startup tab, the registry entry is restored to its original location.

If System Configuration Utility is unavailable, manually clean-boot your computer. For additional information about how to manually clean-boot your computer, click the article number below to view the article in the Microsoft Knowledge Base: 243039 How to Perform a Clean Boot in Windows 95

If the computer no longer exhibits the behaviour, you can narrow the focus of the behaviour. To do this, you must use System Configuration Utility to restore files or file entries until you determine the specific entry that is causing the behaviour. This process is commonly referred to as "restoring by halves" because you restore half of the entries that you previously removed, restart your computer, and then you test to see if the behaviour continues to occur:

1. Click to clear all of the check boxes in the Selective Startup section on the General tab in System Configuration Utility, click OK, and then restart the computer when prompted to do so.
2. If the behaviour continues to occur, use the Advanced Troubleshooting Settings tab in System Configuration Utility.
3. If the behaviour continues to occur, restart your computer in Safe mode and test. If the behaviour continues to occur when you restart your computer in Safe mode, contact Technical Support.
4. If the behaviour does not occur when you click to clear all of the check boxes, click to select both the Process System.ini File and Process Win.ini File check boxes, restart your computer, and then test to see if the behaviour still occurs.
5. If the behaviour does occur when both the System.ini and Win.ini files are processed, the behaviour is related to one of the files. Click to clear the check box for only one of the files. If the behaviour occurs, an entry in the file that is selected is causing the behaviour. If this is true, go to step 8.
6. If the behaviour does not occur after you click to select both the both the Process System.ini File and Process Win.ini File check boxes, click to select the Process Autoexec.bat File check box, restart and then test to see if the behaviour still occurs. If the behaviour occurs, an entry in the Autoexec.bat file is causing the behaviour. If this is true, go to step 8.
7. If the behaviour does not occur after you click to select the Process Autoexec.bat File check box, click to select the Process Config.sys File check box, restart and then test to see if the behaviour still occurs. If the behaviour occurs, an entry in the Config.sys file is causing the behaviour. If the behaviour does not occur, an item in the Startup group or in the Winstart.bat file is causing the behaviour.
   1. Click to select the Process Winstart.bat File check box, restart and then test to see if the behaviour still occurs. If the behaviour does not occur, an item in the Load Startup Items section is causing the behaviour.
   2. Click to select the check box on the General tab for the file that you determine is causing the behaviour,
   3. Click the tab that represents that file,
   4. Click to clear the bottom half of check boxes in the list, restart and then test to see if the behaviour still occurs.
   For example, if an entry in the Config.sys file is causing the behaviour,
   1. click to select the Process Config.sys File check box on the General tab,
   2. click the Config.sys tab,
   3. click to clear the bottom four of the eight check boxes is the list,
   4. click OK, and then restart when prompted to do so.
   5. If the behaviour continues to occur, one of the check boxes that you clicked to select is causing the behaviour. If the behaviour does not occur, one of the check boxes that you clicked to clear is causing the behaviour.
   6. If one of the check boxes that you clicked to select is causing the behaviour, click to clear half of the remaining check boxes that are selected, restart your computer, and then test to see if the behaviour occurs.
   7. If one of the check boxes that you clicked to clear is causing the behaviour, click to select half of the check boxes that you clicked to clear, restart and then test to see if the behaviour occurs.
   When you follow these steps, you can isolate the specific file entry that is causing the behaviour after you restart your computer several times. After you determine the specific file entry that is causing the behaviour, it is recommended that you edit the appropriate file or registry key to remove this entry, and then return System Configuration Utility to the Normal Startup option.
8. If the entry that is causing the behaviour is in the Config.sys, Autoexec.bat, Win.ini, or System.ini file, use the System Configuration Editor tool (Sysedit.exe) to edit the file and disable the appropriate line or lines:
   1. Click Start, click Run, type sysedit in the Open box, and then click OK.
   2. On the Window menu, click the appropriate file name (for example, click C:\Windows\System.ini).
   3. Type rem followed by a space at the beginning of the appropriate line that is causing the behaviour.
   4. On the File menu, click Save.
   5. On the File menu, click Exit.
   6. Restart your computer.
9. If the entry that is causing the behavior is a program that is on the Startup tab, remove the program from the Startup folder or delete the program from the registry. To remove the program from the Startup folder:
   1. Click Start, point to Settings, and then click Taskbar And Start Menu.
   2. Click the Start Menu Programs tab, and then click Remove.
   3. Double-click Startup, click the appropriate entry, and then click Remove.
   4. Click Close, click OK, and then restart the computer.
10. If the entry that is causing the behavior is not in the Startup folder, the program may be loading from the registry. To remove the entry from the registry:
    1. Backup the registry and make sure you understand how to restore it
    2. Click Start, click Run, type regedit in the Open box, and then press ENTER.
    3. In Registry Editor, locate and click the following registry keys, one at a time, and then click Export Registry Key on the Registry menu for backup purposes: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
       -and-
       HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
    4. Delete the file_name.exe value in the right pane for the appropriate registry key, where file_name is the name of the file that is causing the behavior: HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
       -and-
       HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
       -and-
       HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnceEx
       -and-
       HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    5. Quit Registry Editor, and then restart your computer.

• Troubleshooting Example

The information here applies to:

• Microsoft Windows 98
• Microsoft Windows 98 Second Edition