Hard drive won't show up in explorer

Hey everyone, I just got a Western Digital Caviar Black series 500 GB SATA II Hard drive, and put it into my computer as a slave drive. I have the RC and all drivers are installed correctly. The drive shows up in the bios, and in device manager, but when I go to computer, it does not show up. Another interesting fact is that when I stuck it into a different computer, when I tried to install Windows (XP and 7 RC) both installations failed to find the hard drive... I'm confused! Any suggestions?

Try this:

Go to the console and type "diskpart" (no quotes)
Type "list volume"

If your drive shows up here, but has no letter associated in the "Ltr" column, all you need to do is assign it one. You can do that as follows:

Type "select volume x" where x is the number corresponding to the hard drive
Type "assign letter Q" where Q is the desired drive letter (recommend a letter between F and W, because some applications map drives X, Y, and Z for emulation)

If that was the issue, you can quit out of the console and your drive should appear in the Computer menu. Good luck!

What if the drive does not show up under diskpart but shows up in the bios?