Most likely not the issue here, but I've connected a floppy drive cable backwards. It ends up corrupting the floppy and is frustrating b/c the drive light comes on and it looks like its working. I munched several boot floppies this way before figuring it out. If you're not booting from the floppy you can boot all the way up to the OS (at least W2k) and still have a: show up, although it's not functional in the least.

-Zeke