JIT is right; we need more detail. Let me add to the questions:
If it's a new drive, see this: http://www.tomshardware.com/forum/265764-32-guide-installed-disk-system
If it's a drive that worked before, and has data that you want to access, we need to know just how far up the line it can't be seen, again as JIT wrote. Is it detected in BIOS, in the device manager, in the disk manager?
psychic, but I can't read your