Why would all USB devices now be Not Recognized in Vista?

Working Devices suddenly are not recognized. Internal AcerOrbicam failed, flash drive failed, mouse failed, digital camera failed. All were working for a long time??? Suddenly all are device not recognized?? Tried Regedit and removed usbstor to force re-id of devices – no luck. Driver re-installs say no device? Also removed-reloaded USB hub controller device managers, which re-installed and again detected “Unknown Device”. Vista on Acer Aspire 5100, many different Oribicam models used and cannot find out which is in this laptop (not even from Acer!!). Do not suspect camera problem, just USB failure.