NOW, from the sound of things here, it seem you have borked the USB ports. Most likely you have Electrically shorted out the ports to where they do not work at all and probably will not work ever again.
Scott54 was on the right track, even if it costs a little bit of money. A 4 port USB PCI card may give you back your USB ports so a keyboard and mouse can work. Beyond that i think you are looking at a motherboard replacement.