Something using CPU power but i cant identify it!

[413x]

My cpu usage is sitting at 13% with the CPU multiplier locked at 21x

i cant identify it in the applications area of task manager wither, i only noticed as my cpu gadget is reading spikes,

any ideas? should i run a virus sweep?

 

[413x]

thnaks for the help, it was indeed a virus, vundo variant-msfake,

noticed it when trying to play a game, stuttered when it didnt before, thought it was xfire linked but then i saw the cpu, couldnt locate the culprit, superantispyware found it, malware bytes didnt!

Never had a virus before, and i didnt have it [or at least the effects] 3 hours ago!