I see this from time to time. As far as I can tell, I have installed nothing that should alter the way Windows XP Pro, SP-2 works but on some reboot something changes. The most recent example is when Opening the "My Computer" Icon, I used to have a space and a line entry separating the "Removable Media" from the Hard Drives. Yesterday for some reason my machine started displaying all the devices without a divider.
I have lots of anti-virus, anti-scripting programs and nothing gets updated automatically. The ONLY thing I did at all was update my AVG anti-virus program. That should have no effect on the My Computer device display?
I've seen this on lots of other mnor issues like one day "Tray Commander" stopped working. I deleted and reinstalled with no joy.
Little irritants. Any explanation?