Make sure the USB controller is enabled in BIOS.
If ok, then check for any problems with the USB controller in Device Manager. If so, then make sure the MB's chipset drivers are installed.
If things are ok in Dev. Mgr., then see if it works on a different USB port. If not, then see if another USB device works. If not, then make sure SP-2 is installed. If so, then the USB hub may be bad. A USB PCI controller can be installed as a work around.
If another USB device works ok, then try the scanner on a different system. If no good, then it may be bad.