Perform a system Restore using a restore point prior to the loss of the USB.
Then check these areas:
• The Device Manager
START | type dev man into the Start Search box | right-click on Deice Manager that appears up top | select Run as Administrator | look for any red/yellow flags - pay specific attention to the USB area.
Problem Reports and Solutions -
START | type wercon.exe into the Start Search box | right-click on wercon.exe that appears up top | select Run as Administrator | view "See Problems to Check".
• The Event Viewer -
START | type eventvwr into the Start Search box | right-click on eventvwr.exe that appears up top | select Run as Administrator | view the various logs starting with the Administrative logs.
• Reliability and Performance Monitor -
START | type perfmon into the Start Search box | right-click on perfmon that appears up top | select Run as Administrator | view both the Performance Monitor and the Reliability Monitor.
The other thing that you can try is to go to the control panel, select Sytem, select hardware click on Device manager and scroll to Universal serial bus controller and Right Click on the USB Root Hub and select uninstall, You might even have some that have a triangle on them identifying an error or even crossed out red. Delete all those. Once deleted a restart of Vista should find your USB ports and identify it as new hardware and install it as new hardware.USB is Plug-N-Play and Vista will find the drivers for you automatically.
If this does not resolve your issues, you may have to check the bios of your computer and see if it displays anything with the BIOS but try this first and get back to me...:) good luck