seems that my pc has corrupt usb drivers when windows 7 loads. before win7 loads, usb ports work in bios & repair mode. doesn't work in safe mode. both usb2 & usb3 ports don't work. to add to the problem the pc only has usb inputs, so I can't get the mouse and keyboard working to log into windows to maybe try to uninstall in device manager. I tried a restore point but none get it back before they got corrupted. I was thinking if I can just overwrite usb driver files through command line in recovery/repair with default drivers maybe I can get it working. whats the syntax for that? the pc is an Alienware X51 R1.