Originally Posted by JBeaucaire
Last ditch...are you trying to use the USB ports on the FRONT of the computer? Those are usually connected internally via a cable that CAN come loose. Odd, but it can happen.
The USB ports on the back of the computer are usually hardwired and might still work if this is the case.
Grabbing at straws here. You could look inside and just see of the cable connecting the forward ports has wiggled loose.
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You could also use the BIOS to disable the builtin USB, then install an addon card of your own to put USB back in. This is probably MUCH less work and cost than a new motherboard.
Bonus, the forward slots might be able to be plugged into this new card, too, so you keep the easy access to the front USB slots.
If you have an empty slot, worth a shot. (rhyme master)