Keyboard stopped working: error code 38

I have a Microsoft Wireless comfort keyboard 4000 that recently quit working. The diagnostics error I get is code 38 "Windows cannot load the device driver for this hardware because a previous instance of the device driver is still in memory. (Code 38)"

I am running Windows Xp with SP 3 on a Medion PC.

Most of the resolutions I find say to reboot, which I have done but no success. I have also:

1) Scanned the hard drive with Malwarebytes' Anti Malware to ensure no infections
2) Performed HiJack this
3) Tried to disable then re-enable the keyboard then reboot.
4) Completely uninstalled the keyboard and reinstalled
5) Uninstalled the keyboard and performed regedit and deleted any keys with an entry associated with Intellitype (my searches in regedit are very limited since I cannot type)
6) Opened file manager and manually deleted the drivers but they seem to reappear after a reboot.

Hoping someone can help me. I have exhausted everything my limited knowledge knows what to do.

Also, what is a good registry cleaner for programs/software that I no longer use that are still in my registry, i.e. Zone Alarm, My Space, Mozilla etc

Thank You to All