Win explorer says there's xtra drives that don't exist?!?!

[brooose]

My system has 4 physical hard drives: two 250 gb drives and 2 110 gb drives with no raid array.
Each 250 is partitioned into 3 parts and each 110 just with 1 each. A month ago I reformatted my C partition only and reinstalled xp on it. I went into disk management and checked to see everything was ok. In windows explorer though, there are two "Local Disk" drives that don't exist.
You can't format them and the properties box says for used and free 0 & 0 bytes.
Disk management doesn't see them, but windows still thinks they are there, but you can't do anything with them. These pesky drives are taking up letters I want to use for other drives and I can't get rid of them.
Any ideas what master list they are coming from or how I can get rid of them??
Thanks.