THIS MAY HELP...
1. Click Start, right-click My Computer, and then click Properties.
2. Click the Hardware tab, and then click Device Manager.
3. Expand Universal Serial Bus controllers, right-click USB Root Hub, and then click Properties.
Note There may be more than one USB Root Hub installed in your computer. In this case, you may have to follow these steps with each USB Root Hub device.
4. Click the Power Management tab, click to clear the Allow the computer to turn off this device to save power check box, and then click OK.
5. Quit Device Manager.