Nothing. This is the first sign of USB port failure. So if the machine is still under warranty, call Gateway/Acer and make a warranty claim for a new motherboard. Otherwise, soon other ports will follow, and eventually they will simply stop working at all. Much as I like to blame Acer for competing with HP to build the world's worst quality machine, in this case they're completely innocent. The design of USB ports is very very poor. It's almost designed to fail. So, either call Acer about making a warranty claim, or accept that this is the first sign of the slow death of your system's USB ports.