My computer had been working fine, however recently the 2 usb ports just stopped working. Having checked everything I've thought of, I've found they still are seen by the computer as working fine. The devices I hook to it show they are connecting, but nothing is working. I've tried my external hardrive, memory stick, cameras, a printer and a dvd burner. The computer just doesn't read them at all as connected. I've tried them on my other two desktops in the house and eveything works fine. Anyone have any advice that could help me?