The drive is going to die, and going to die soon. Get everything off of it right now.
Sometimes things like this will come and go for a while. Occasionally I've seen low level formats "fix" drives making weird noises, but it never lasted long. Most disk checking software will mark bad sectors on the drive, which can also make it appear as though the drive is "fixed", when the root problem is simply masked. There is nothing that software can do for you...clicking noises and/or drive respinning + lockups = mechanical problems...they may in some cases be caused by external factors, but once the drive starts to make noise, it shouldn't be salvaged.
If the drive is < 3 years old, then it is most likely still under warranty. All of the big manufacturers have very easy replacement procedures, and you can often get an RMA right online without any trouble.
If it is under warranty, it would help to take Emeric's suggestion and run some diagonstics on the drive (from the manufacturer's website), because in some cases they'll want you to (e.g. IBM kind of hassles you for information before giving you an RMA, whereas Maxtor doesn't require anything but filling out a form).
Remember, NOISE = DEATH. I have yet to find a case where a drive was making bad noises and it continued working or "fixed" itself. I've gone against my better judgement on this one (recently, in fact), and got burned badly. Of the 10-15 drives that have died on me in the last 5-6 years, just about every single one started with clicking noises or with the drive spinning down/up at inappropriate times (e.g. any time other than bootup!).
Slackmaster 2000
