Tell more to see if the forum can see if there is a reason for it to fail.
Looking at a hard drive from a Win XP PC for a friend. His PC fails to recognize that it has a hard drive, so I took it home and plugged it into my USB caddy. It makes the characteristic sound, but nothing shows up in My Computer.
I went to Administrative Tools and clicked Disk Management. Nothing new shows up there, either.
The drive is warm, and is vibrating slightly, but I get no evidence that it is working. Is it dead?