I can't answer your problem but MS will give you free assistance for a problem with updates.
If you go to START/right click on My Computer/Manage/Disk Management, does it not show up there either. Or how about in Device Manager?
At this stage, I would probably go back to Windows Update and see if a later KB is available which could possibly fix your problem. MS only supports XP2 now, so you could find a heap of updates to install.
Edited by rowal5555, 03 June 2007 - 09:26 PM.