Unknown Device

Acer Veriton 1.7ghz/S82MA Mobo/running win xp pro corp, in device manager/yellow ? other devices/unknown device,. Windows xp wont load driver for this device, have d/loaded drivers from Acer site but cant get any to work. I have also tried windows xp pro sp2, same result. Can anyone help me please as this is sending me round the bend. Any suggestions greatly appreciated.