Mal som taký problém , že mi nefungovali v systéme žiadne USB myši. Pomohlo mi toto :
1. Open %windir%\inf folder.
2. Backup and delete these files:

- INFCache.1
- msmouse.pnf
- input.pnf

3. Open a command line and run
Net stop Cryptsvc
4. Backup and delete this folder “%windir%\system32\catroot2”
5. Reboot the computer to make sure the information was clean up.
6. Insert USB mouse to another port which hasn’t been used before.

7. Uninstall all HID devices than "Scan for new hardware"

zdroj http://social.technet.microsoft.com/forums/en-US/i tproxpsp/thread/8a46e6bf-bafa-4d68-91f3-d6ba2e3039 a9/

Len neviem či to zvládneš spraviť klávesnicou. Predpoklad je, že ten systém funguje-nie je "zmrznutý". Vtedy nefunguje myš štandardne.