This is not actually a "driver", but it is a file needed by the HP ScanJet 5100C before it will work properly with Windows 2000.
The Instructions are as follows (and follow them EXACTLY)
Install ScanJet Software that came with your scanner FIRST --- BUT DO NOT REBOOT!!!!!
Choose the "reboot later", then run this program -- BUT DO NOT REBOOT!!!!
Delete the Program Reference in the "Start" Menu under the Programs Menu (HP Parallel Port Test)! (VERY IMPORTANT)
Once that's done, THEN reboot.
Hope it helps!