I use a Mac Pro (early 2008) at work. It has the latest Mavericks installed. Lately the USB ports seem to be failing. First the two on the front stopped working, and now two out of three on the back stopped working. Does anyone know of a way to reset the ports or test them? I've tried repairing permissions, an SMC reset and a PRAM reset but those failed to do anything. Is there anything else I can try?