When you exit an MS-DOS program, Windows 2000 issues:

<b>Invalid COMMAND.COM
Cannot load COMMAND, system halted</b>
The MS-DOS windows stops responding.

The problem occurs because the ComSpec environment variable is not set to a CMD.EXE file.

To resolve the issue:

1. Close the hung window or use Task Manager to End Task.

2. Use Notepad to edit %SYSTEMROOT%\SYSTEM32\AUTOEXEC.NT.

3. If a ComSpec= line exists, remove it.

4. Start / Settings / Control Panel / System / Advanced / Environment Variables.

5. Select the ComSpec line and press Edit.

6. Set the ComSpec Environment Variable to:

    %SystemRoot%\system32\cmd.exe