CPU usage problem

[MusikDisaster]

I keep having a recurring issue where my CPU usage randomly blows up to 100% and my games, WoW included, drop to around 1 fps, if not 1 frame per 5 seconds. I usually play most games on Full with around 55-60 fps.
I wait a minute or so and it stops, but it's annoying and I don't know what the problem is.
Specs:
Windows 7 Home Premium 64bit
Dell Studio 1745
Intel Core 2 Duo 2.8 GHz
3 Gigs Ram
ATI Mobilty Radeon HD 4650

Not the most glorious computer, but it's good enough. Please no "omglol ur cpu lol suxxorz mine r bettar" posts.
Thanks in advance

[chaud]

Run http://technet.microsoft.com/en-us/s.../bb896653.aspx , look for the spike in a processes CPU usage, and you will know what it is!