I've been fighting this one for some time and still haven't figured out what caused it or how to fix it. I have a P205 s-6287 Tosiba laptop, 4gb ram, windows 7 home premium 64-bit OS.
Under the Computer icon I have a phantom local drive (Q) showing up. If I click on it "it is not accessible", "access denied". I can't find it in Device Manager or Computer Management. I did find it in registry and deleted the key, but after a reboot it returns.
The only thing I can think of that I did different was I tried to access my card reader through a usb port with an adapter, but that didn't work. I then accessed the built in reader and it worked fine. Maybe I removed it without clicking on the safe to remove icon -- can't remember.