Keyboard problem.

[Hotbrick]

Sometimes, for no apparent reason, my input devices (keyboard, ultranav, trackpoint) just stop working.
The only way to get it all working again is to disconnect AC and take out the battery, or connect with my bluetooth mouse and shut off the normal way; and restart.
Any suggestions what causes this? Solutions?

[richk]

First, look in the event viewer. See if there is a message.

[Hotbrick]

Thanks for your reply RICHK.
Problem is solved ; Perfectdisk messed up things somehow....