The 80GB drives were a little bit noisier that the 60GB drivers. Both; however, should be very very faint and you should not hear any noises unless the fans are completely off and you try read hard to hear it.
I would suspect that your HDD may be going South on you. Might be RMA time.
If it is still under the warranty period they will. Send them an email and follow it up with a phone call/voice mail. Include you serial number and model number in the email, as well as, what the sympthoms are.
Be careful! When my hard drive started making these weird clicking sounds, i only had about 4 days left before it just wouldn't start up anymore. If i were you i would try to back up anything you have on there ASAP, then email sager to get an RMA for it. When I sent mine in they sent me a new one in a few days.