In Deep Trouble!

Please help guys if you know of any solution, my external drive stopped showing up, the computers read it and install drivers but there is no drive letter, I tried running spinrite on it but it seems as though it can only read the internal drives. Anything else I can do. I'm using vista ultimate, and I can not figure out a way to get the volume to be read. Disk manager doesn't even show a drive letter for it. Is there anything I can do?

a bios update might work but i would save that for last.system resstore back a couple days see what happens..