hd diagnostic tool?

Is there a diagnotic tool out there which can test the hard drive for performace?
I think one of my drives is about to drop

My computer is hanging every 20-30 minutes for about 1-2 minutes a piece, completely unresponsive. No bluescreen or error, just unresponsive. Mouse wont move at all.

Updated XP, updated antivirus/scanned, updated adaware,spybot. Chkdsk, defragged. Still have the problem

Sometimes I've noticed when the problem stops a small sound comming form the box, and it sound like a hd starting to read. I could just be paranoid.