All of my USB ports have quit working. I booted up from DVD and the mouse works just fine. I then (while in DVD mode) went to Disk Utilities and "repaired disk" and "permissions" and they went fine. It looked like a few things could've been repaired I just don't know how to read logs. But when I rebooted from internal HD USB ports still aren't working. So it looks like a HD issue. Would installing OSX and apps again make USB work? Thanks.