8200 Any little activity causes excessive processor use

I have a 1.8 Inspiron 8200. It has been running very slow so I used task manager to monitor activity and I notice any little activity cause the processor to go to or almost 100%. Even when it should be about idil there is about 15 to 20% activity. I did several virus scans and didn't come up with anything. I also tried to backup a lot  of my hard drive incase of a possible hardware failure and this ended up be so slow I need to cancel. It was going to take over 24hours to back up the 30 gig drive. Any ideas?