I just got through fighting my desktop for not seeing my daughter's new ipod through known good usb ports. Even after updating the drivers from the mobo mfg site, it still wouldn't work. I stumbled across someone else's solution to a similar problem and it worked for me. Turn off the computer and disconnect any and all power sources (battery, wall plug, etc) and let the residual power drain (I hit the power button a few times). Reconnect the power, fire it back up and then reconnect your usb device. I don't know why, but it worked for me.