USB ports stop working

[OldManClayton]

Didn't find anything in a search. I'm using an X61 Tablet running Ultimate.

All is dandy until I unplug my USB devices (Those being a USB hub with a mouse, printer, and hard drive and an ipod on another port) and step away from my desk for a while. Sometimes when I come back and plug everything in, Vista doesn't recognize it. Neither the hub nor separately plugged-in devices work. My ipod's screen will come on but it won't charge and the lights on the hub stay off.

Only way I can ever fix it is to reboot, though one time it decided to start working right after I hit the shutdown button. (Need to make a shutdown cancel bat. XD)

Any input? I went into the device manager but it keeps freezing whenever I scan for plug and play hardware. Probably because an unknown device has appeared whose identity I've yet to determine.

Thanks all!