Can you use a PS/2 connection and remove the USB and keyboard drivers then restart and re-install them? Any BIOS settings for the USB's that might be of use? Perhaps resetting the BIOS might have an impact?

It is weird that all the ports don't work. I suppose I could see something like a metal peice shearing the cables and it happened to jump the hot and ground cables damaging that perticular port, but all of them is kind of weird.