Computer crashes when left idle with a dialog up or in lock screen mode.

[ol1v3r]

Hey guys,

Ive noticed recently ive come home after leaving my computer on, i'll switch my screen on, and theres say a error dialog or something up. I am unable to move the mouse at all, and it results in me having to switch the thing off at the wall. The hard drive light stays on too when its crashed. This is the same for lock screen mode as well

I'm am currently running Windows XP Professional with service pack 1. And i have the following hardware installed:
- Leadtek Winfast TV2000XP Expert TV card.
- AGP Sapphire RADEON 9550

I have AVG Free Edition anti virus running also.

Thanks alot guys,
Oliver