Problem with S.T.A.L.K.E.R. Call of Pripyat

Hey all, i've got bit of a problem with the said game. it was working fine 2 days ago, and then yesterday all of a sudden when i start the game up, it starts in a small window (takes up a little less than a quater of the screen) when i eventually mange to get it into full screen mode again, when i try to load my game it just freezes the game. I was wondering if anyone knows how to fix this problem.

Thanks in advance

GENER-AL

I don't know if this would work but you can try deleting your configuration files (user.ltx)then starting it again. It worked when a particular configuration didn't worked (freezed) in my PC.

Btw you should make a backup before you do that.

hey guys thanks for your help, in the end i just made a backup of my save files and un-installed then re-installed the game, its working now. now i just need to figure out why when i watch video, play games or have multiple windows open, my laptop starts to lag for 2 mins then is fine for 5 mins then lags again, it says that 100% of the CPU is being used but i know its not cos theres nothing using it all on task manager =/