I have 5 HDD installed. One of them is clicking a lot lately. Is their HDD software that can check a drive to see if something is wrong? Or maybe HDD monitoring software that would notice a HDD that is clicking?

I'd rather not backup everything on all 5 HDDs if at all possible (well, only 4 HDDs since the boot drive is expendable).

I would back up that drive ad do a rma on it. clicking is never a god sound from a harddrive.
as for testing, the manuf. should have diag software.

I think what he means is that he doesn't know which drive it is, and doesn't want to backup all 5 or pull each one individually to see which is clicking.

YES!

Plus, I don't think any of the drives are still under warranty excpet for maybe the Raptor (74GB). I believe the Raptors have a 5-year warranty, but that might be past already. I'll try the manufac. diag. tools and see what happens.

pull the power on all, boot up system and if sata then hot plug the power cable into each drive one at a time until you find a clicker.

Sometimes the clicking doesn't happen for hours. I've been trying to perform some action that will get a click every time. I've been scanning and tesing all the HDDs with the manufacturers diag apps and nothing has come up yet. The problem is the boot drive is being used all the time. I'm slowly moving the data off the drives to another computer or to DVD. Then I start eliminating each drive. All of the drives are 4+ years old. Guess it's time to replace them all with a single 2TB drive.

with the cost of tb drives being cheap, I'd retire them.
I retire my drives every two years, and when I do I replace them with larger drives, went from 500gb drives to 1tb drives which reduced the amount of drives and kept the old ones as backups of data.

I keep the old ones around for when I can't find a hammer.

Yeah, the 1TB HDDs are pretty cheap. Any recommendations?

I saw the SAMSUNG Spinpoint F3 HD103SJ 1TB 7200 RPM 32MB for $60 shipped. I usually go WD these days (love my Caviar Black 1TB in my testing rig).