My windows 7 locks-up randomly, but only USER INPUT!

Hello,

I am experiencing lockups of my windows configuration, even when reinstalling my windows 7 from scratch.

However, when my pc locks, it seems that only the mouse and keyboard freezes, because i see that background tasks are still working:
- Drive leds are still flashing
- When i was running a backup tasks, i saw the backup device leds also flashing.

How can i detect what is the culprit to resolve this issue?

I get no BSOD.

best regards,
Sven

What type of keyboard and mouse are you using? Are they PS2 or USB? You might want tro try PS/2 mouse&Keyboard to see if they works on yours