high cpu usage

[Tantrum]

I have an intel core 2 duo e8400 3ghz cpu. Win 7 32 bit OS.
my cpu usage is always 70 to 100%.
I tried formatting my computer and it didnt work. I ran any possible antimalware program there is, and nothing.
I can also say its not overheating because it has a very strong working fan on it.
and recently it has been shutting down for no reason.
help me!
Thank you

 

[Subhra133]

Go to start, and type "system configuration" then go to the "Startup" tab and uncheck all that is not from Microsoft, restart and see if this fixes the problem.
Also i recommend to use a software called ccleaner. Check all boxes and run it.

 

[Tantrum]

Tried both, didn't work.