Go to Control Panel, Hardware, Device Manager. If the USB section is yellow flagged as faulty I would delete the device and click refresh. The system should then seek the correct driver -- if problems direct the search towards Windows folder, System and System32 subfolders.
If this doesn't work, after deleting the device, restart Windows a couple of time to rearrange resources and see if the USB reinstalls itself correctly.
If the problem has occurred after a Windows update see if Toshiba site has a more recent driver pack for your computer.