I would try to localize the sound. It may be that some part of the computer is merely vibrating in synch with the natural frequency of the hard drive.

In my Insprion 1150, I had a problem with a clattering noise when certain keys were pressed. I removed the keyboard to find that its metal keyboard frame was flexing against a thin metal plate. I placed electrical tape between the two parts and the clattering went away.

I would remove and reinstall the hard drive, but also check to see if there is any sheet metal material connecting to or laying close to the drive; it may simply be vibrating in tune with the drive. I would not assume that it is a hard drive mechanical problem.

Most hard drives have detailed diagnostics available; for example, Hitachi has great diagnostics for the "Dell" Hitachi drive in my 1150 on the Hitachi web site.

Run whatever diagnostics you can while also working on reseating the drive. Be careful NOT to run any tests that destroy data or erase the drive in the process, however.

thank you for the replies. I reset the hard drive this morning and there was nothing that would appear to be rubbing against the drive. When i reset it, the sound remained. However, when i took the hard drive out of the computer and rotated the hard drive, it sounded like something was loose inside. I found it to be suspect so i contacted Dell. They have ordered me a new hard drive and i will be getting it shortly. Ill let you all know how it turns out. thanks again