Uninstalling Service Pack 2 on Windows 2000
You can uninstall Service Pack 2 by running the uninstall program from the command prompt.
1. Click Start, and then click Run.
2. In the Open box, type cmd, and then click OK.
3. Type cd %systemroot%\$NtServicePackUninstall$\spuninst\, and then press ENTER.
4. Type spuninst.exe, and then press ENTER.
5. To close the Command Prompt window, type exit.