I'm guessing that you need USB2.0 but you are either using USB1.0 or your USB controller is packing in and only recognizing devices at USB1.0 speed.

In either case, you would probably be best to find a cheap PCI USB2.0 controller and install it; that should give you the required data rate.

It also may not be the bandwidth from the USB controller causing the problem, but something bottlenecking the CPU (etc.) so that the instructions aren't reaching the USB device quickly enough. That would be a matter for a PC technician, as it likely means some part of your computer is dying.

EDIT: Way to upstage me Azar. :{