High CPU usage in Vista

I just received my Dell E521 Desktop. Since I started it, I have had a consistent cpu drain ranging from 2% - 60%. The usage bounces around and it does it when the computer is idle. It bounces between percentages every 2 seconds or so.

 

It only does this when connected to the internet and via the task manager apperars to be one of the many scvhost.exe that is causing the drain. I have tried just about everything, Ie; stopping windows update, checking for viruses, adware, etc, however I still have the same problem.

 

Can anyone please help!!!!!!