CPU Usage/ CPU Load

I have a problem with my notebook and i'm not too sure how to fix it, or whether it can be fixed. I have an inspiron 1150, 2.8GHz, 512mb ram, blah blah. Basically, when my computer is sitting idle, not running any programs, the cpu usage is around 2-4%. No problem. Then, when i run basically any program, it takes a jump to 100%. It will drop to a lower level for maybe a second or two. I know i don't have any programs running in the background as i reformatted my hard drive clean and fresh. i only installed the drivers i needed, and a few spyware checking programs. Is there a setting somewhere or a program that can throttle the cpu usage?