No Video Files playing on any player

Hi peeps,

My laptop has stopped playing all types of video files, all audio files plays fine.
I haven't installed any software, all I did was boot and suddenly when I launch ANY video player
(WMP, VLC and IrfanView).

When I load any video, the player loads but then crashes (" x has stopped responding").
I have another partition with Windows 7 Home Premium and it loads videos fine.
I've scanned with Spybot and Avast, with only 2 infections being tracking cookies.

I use Adobe Premier so I require watching my footage much too often!
Please help!

Edit: I've managed to get IrfanView to load the files and not crash, but it only plays audio.