Virus Detected in the Suhdlog.dat File

Anti-virus programs may detect a virus in the Suhdlog.dat file.

Your computer was infected with a master-boot-record (MBR) virus before you installed Windows 95.

To resolve this issue, use one of the following methods:

Method 1

Remove the virus from the Suhdlog.dat file with an anti-virus program.

NOTE: If the Suhdlog.dat file is damaged when the virus is removed, you cannot use the Uninstall tool to remove Windows 95.

For information about how to remove a virus with your anti-virus program, refer to the documentation included with your anti-virus program or contact your anti-virus program's manufacturer.

Method 2

NOTE: You cannot use the Uninstall tool to remove Windows 95 when you use this method to remove the virus-infected Suhdlog.dat file.

1. In Control Panel, double-click Add/Remove Programs.
2. On the Install/Uninstall tab, click "Old Windows 3.x/MS-DOS System Files," and then click Add/Remove.

If after you remove the "Old Windows 3.x/MS-DOS System Files" component the Suhdlog.dat file is still present, delete the Suhdlog.dat file using the following steps:

1. Click Start, point to Programs, and then click MS-DOS Prompt.
2. type the following lines, pressing ENTER after each line:
   cd\
   attrib -s -h -r c:\suhdlog.dat
   del c:\suhdlog.dat

When you upgrade an earlier version of Windows to Windows 95 and you choose to back up the system files during the upgrade, your hard disk's original MBR and partition tables are copied to the Suhdlog.dat file.

If your computer is infected with an MBR virus before you install Windows 95, the virus is copied along with the original MBR and partition tables into the Suhdlog.dat file. Even though an anti-virus program removes the virus from your current MBR, if the Suhdlog.dat file contains the virus when you use the Windows 95 Uninstall tool to restore the previous version of Windows and MS-DOS on your computer, the MBR becomes infected again.

The virus is not active while it is stored in the Suhdlog.dat file, but anti-virus programs may detect its presence and display a warning.

For additional information, please see the following articles in the Microsoft Knowledge Base: