I had this same problem using Vista and now I am running windows7 ultimate and the problem persists. It seems like there's a quick fix but I can't find my exact problem anywhere on the internet at all...
Basically if I turn my computer on from being off, when windows starts i get all my USb devices BUT if at any time I restart windows (w/o shutting down completely I mean), when windows starts back up, I have 0 USB devices.
Anyone know how to fix this problem? it's a real pain in the ass having to turn my computer completely off all the time and not having the option to restart.
Thanks.