Q. How do I modify the Windows 2000 boot/system drive letter?

A. Microsoft doesn't recommend ever changing the Win2K boot/system drive; however, if an automatic cause, such as a mirror break, changes the drive, you can modify the drive letter as follows (perform a full system backup before you try this approach)—in this example, we swap drives C and D:

1. Log on as an Administrator.
2. Start regedt32.exe.
3. Go to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices.
4. Click MountedDevices.
5. On the Security menu, click Permissions. Ensure that Administrators have full control (change this setting back to its original value when you finish these steps).
6. Quit regedt32, and start regedit.exe (you MUST use regedit to perform the next steps).
7. Go to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices.
8. Find the first drive letter you want to change to a new drive letter. In this example, we look for \DosDevices\C:.
9. Right-click \DosDevices\C:, and click Rename.
10. Rename this value to an unused drive letter (e.g., \DosDevices\Z:) to free up drive letter C to use later.
11. Find the second drive letter you want to change. In this example, we look for \DosDevices\D:.
12. Right-click \DosDevices\D:, and click Rename.
13. Rename this value to the appropriate new drive letter—in this example, \DosDevices\C:.
14. Right-click the value for \DosDevices\Z:, click Rename, and name it \DosDevices\D:.
15. Quit regedit and, if you changed the Administrators permissions setting, restart regedt32.
16. Change the Administrators permissions setting back to the original setting.
17. Restart the computer.