Old OS Appears in Startup Menu When You Upgrade to Windows 2000 (227299)

SYMPTOMS

When you perform an upgrade from Windows 95 or Windows 98 to Windows 2000 Professional and Setup is interrupted during text-mode (while files are copying), Microsoft Windows continues to be displayed in the Startup menu.

Although Windows 95/98 still appears in the Startup menu, after you complete Windows 2000 Setup and restart your computer, you are unable to boot into your previous version of Windows.

One of the following error messages may be displayed:

Windows 95:
Non-System disk or disk error
Replace and strike any key when ready

-or-

Windows 98:
The following file is missing or corrupted: COMMAND.COM
Type the name of the Command Interpreter (e.g., C:\Windows\Command.Com)

You may also receive the following warning and missing file errors:

Warning: Windows has detected a registry/configuration error. Choose, Command prompt only, and run SCANREG.
The following file is missing or corrupted: C:\Windows\Himem.sys
The following file is missing or corrupted: C:\Windows\DBLBUFF.SYS
The following file is missing or corrupted: C:\Windows\IFFSHELP.SYS
The following file is missing or corrupted: WIN.COM

CAUSE

This problem occurs because Setup deletes and moves the Windows 95/98 files just prior to the beginning of the copy process. After the file copying phase of Setup has started, the files marked to be deleted are removed from the system. At this point, you are unable to boot into Windows 9x.

RESOLUTION

To resolve this problem, restart the Windows 2000 upgrade process by selecting "Microsoft Windows 2000 Professional Setup" from the Startup menu.

If you want to return to the previous version of Windows, you must reinstall that version.

MORE INFORMATION

For additional information about upgrading problems, click the article number below to view the article in the Microsoft Knowledge Base: