TSGL: Hard Drive Thrashing

[gene]

Hello Everyone,
    Hope someone can help me with this problem. My hard drive keeps 
thrashing every now and then for a reason I can't figure out.
I have a hp pavilion dv6000. I have tried to isolate the problem but 
it just seems to arbitrarily do it whenever it feels like it. 
Anytime, surfing, working off-line or whatever.
Can anyone give me some ideas i can try to stop it or can't i stop 
it, is it just an inherent thing?
Thanks,
Gene