Open "My Computer" and it shows no C: or D: (DVD-ROM) or E: (second drive).
Same thing goes for opening up "Explore" (not IE).
However, if I select the address bar and type in C: it then shows it, and this works for D: and E:. I think this started from the get go upon installing Vista in August, but can't be sure if it matters.
This is x64 Ultimate on Intel e8400 CPU, Asus P5Q Deluxe, ATI X4850, even though I don't think this is hardware.