Windows Task Manager.

[Azn_tweaker]

before i reformatted my PC my task manager graph was bigger now after my graph is smaller.. and most of the time my CPU Usage is at 90% and above.. and my PF Usage is 122 MB.

[njovin]

To find out which program is using all the CPU, go to the processes tab and click on CPU twice. The first time it will sort the processes by CPU usage ascending (so that the highest-usage process is at the bottom), then second time it will reverse the order so that the program using all the CPu should be listed at the top of that list. If you tell us what the process is that is sing all of your CPU we might be able to assist further.

[Azn_tweaker]

my System Idle Process is always at 98,99 and 100. is that bad?

[Jager-bomb]

Quite the contrary, that's good :-)