How to Save the Uninstall Files Before the Reinstallation of Windows

This article describes how to save your computer's original uninstall files before you reinstall Microsoft Windows.

When you reinstall Windows, Setup may prompt you to re-save system files if the "UninstallDir" line in the Msdos.sys file is missing or incorrect, or if the uninstall files are missing, for example, the Winundo.dat and Winundo.ini files in Microsoft Windows 98.

If you save the system files to the same location as the existing uninstall files, your original uninstall file information can be overwritten. If this occurs, you cannot use the uninstall feature to help you restore your computer's previous version of Windows.

To save your computer's uninstall file information and to restore your previous version of Windows, you must save your current uninstall files in a new location before you reinstall Windows. Decide upon the operating system you want to reinstall, and then perform the following steps:

If you want to reinstall Microsoft Windows Millennium Edition (Me):

1. On the Start menu, point to Search, and then click Files Or Folders.
2. In the Search for files or folders named: box, type:
   w9xundo.* winlfn.ini
3. In the Look In box, click Local Hard Drives, and then click Find Now.
4. Click Edit, and then click Select All.
5. Click Edit, and then click Cut.
6. Double-click My Computer, double-click drive C, click File, click New, and then click Folder.
7. Name the folder Undo, and then double-click the folder to open it.
8. Click Edit, and then click Paste, the uninstall files are placed into the Undo folder.
9. Reinstall Windows Me.

If you want to reinstall Microsoft Windows 98 Second Edition:

1. On the Start menu, point to Find, and then click Files Or Folders.
2. In the Named box, type:
   w98undo.* winlfn.ini
3. In the Look In box, click Local Hard Drives, and then click Find Now.
4. Click Edit, and then click Select All.
5. Click Edit, and then click Cut.
6. Double-click My Computer, double-click drive C, click File, click New, and then click Folder.
7. Name the folder Undo, and then double-click the folder to open it.
8. Click Edit, and then click Paste, the uninstall files are placed into the Undo folder.
9. Reinstall Windows 98 Second Edition.

If you want to reinstall Windows 98:

1. On the Start menu, point to Find, and then click Files Or Folders.
2. In the Named box, type:
   w98undo.* winlfn.ini
3. In the Look In box, click Local Hard Drives, and then click Find Now.
4. Click Edit, and then click Select All.
5. Click Edit, and then click Cut.
6. Double-click My Computer, double-click drive C, click File, click New, and then click Folder.
7. Name the folder Undo, and then double-click the folder to open it.
8. Click Edit, and then click Paste, the uninstall files are placed into the Undo folder.
9. Reinstall Windows 98.

NOTE: After you reinstall the operating system, you must download critical updates from the Windows Update site again.