I have the same problem. Sometimes closing the explorer and reopening it corrects the problem. Sometimes I have to re boot to get the drives back i the explorer window or the computer window. The top line of the display moves from left to right as if the program was looking for drives and can...
Itried ending the explorer and restarting it, but it didn't work for me. I had to boot!!!! I've never seen this under XP, unless it was one of those explorer hangs that ended in a boot.
When i attempt to open explorer or computer, nothing displays and alll of the icons are circling as if looking for data. This has happened 3 times, and a boot always corrects the problem. Anyone have a similar experience?