First, remove the previous drivers, including the corresponding oem.inf (make sure you don't delete the wrong one) file in the WINNT/inf directory. Then, unplug the scanner from the computer. Reboot. Then install the new Win 2000 drivers from Acer's website. Then power down the computer. Re-attach the scanner and power it on. Then power up the computer. The scanner should be recognized and the drivers should work now. That's how I got mine to work.
Good luck,
Bob