Help!!!

i run vista and when we first got the laptop cs and other games were running very very smoothly now all of a sudden most of the time the processor seems to be working very hard(engine like sound...then back to normal sometimes). i have a hijack report from systemcare3. is there anything else i could show you guys or is there anything i can do to fix this problem. cheers, and sorry for my noobness.3gb RAM btw