Solution: Mouse and/or Keyboard not Working after Deleting Upper/Lower Filter in Registry
Scenario: Mouse and/or Keyboard not working after deleting entries in the Windows Registry (regedit) to fix CD/DVD problem (Upper and Lower Filters)
Reason: There are three entries of Upper and Lower Filters in the registry. The first entry is for the CD ROM. This is the only entry you will need to delete in order for your optical drive to work. The second and third entry is for the keyboard and mouse and you should not delete it or your mouse/keyboard will not work at the next restart.
Original upperfilters entry
System Restore can do the trick but obviously you cannot do it because your keyboard and/or mouse is not working.
You can try this method instead: Restart your computer and before the Windows XP logo shows, repeatedly press F8. Choose Last Known Good Configuration. Try this several times if it doesn't work the first time.
Or if you're just like me (keyboard is working, mouse not), navigate through the registry and restore the deleted entries as shown in the screenshots above.
If the above methods don't work. You will need to use a bootcd that is capable of navigating the registry. One example is UBCD4win.
There will be several entries of these. Look for the keyboard and mouse entries (refer to screenshots above) and restore the upperfilters entry.