My friend has just bought a Packard Bell pc with 4 usb ports, 2 on the front and 2 on the back. One is used for the mouse/keyboard, the other on the back we tried to connect a scanner to. The scanner software is installed properly but it cannot findthe scanner. When I swapped the scanner usb with the mouse/keyboard, a message came up saying a new device has been found, but the mouse/keyboard won’t work. The system is running Windows XP. The scanner is Visioneer. Do you have any ideas?