BIG problem!!! my harddrive loads nonstop

[brendin]

a few weeks ago i noticed while trying to sleep my hard drive was loading continuously so i went to my computer so see wuts up when i unlocked my computer it stopped loading. now when gaming (last 2 days) my computer lags really bad and its getting worse my harddrive loads almost nonstop and its hard to game

vista ultimate 64 bit SP1
COD4

 

[Scotteq]

Run a virus and spyware scan