read disk error

I have an inspiron 1000 and when i start up i get the message " loading prb 2 " then i get a "read disk error" and i have no idea whats goin on with computers i was reading the message boards and someone had a similar problem and they where told to run a diagnostic but i dont know how to do that and also to remove the hard drive and reset it aslo i have no clue could appretiate any help. thanks