monitor turning all different colours.

[Brailor]

first of all hi guys i am new to these forums, and just wanted to post a problem i am having atm.

i play games on my laptop and sometimes my screen goes black and then it goes through a colour cycle of red, green, blue and it keeps going through this cycle and will not stop until i power it down, it does not do it with all games i play i play WoW and it never does it once on that my card does get a little hot sometimes but never overheates.

the games it has done it on so far is : Modern warfare 2, left 4 dead 2, and recently the new AVP game.

my system specs :
intel core 2 duo 2.1ghz
4gig Ram
320gig hard drive
ATI mobility Raedeon HD 4670

would really be apreciated if someone can help me thnx for reading this post.