How to get an old Canon scanner (which has no XP drivers) working in Windows XP: Use Win2000 scanner driver, but follow this procedure (on Canon’s German site, but written in English).

In summary you make sure the scanner is DISCONNECTED; then use the old Setup.exe to install the software; shut down the PC and THEN plug the scanner in. When you start the PC up again, it’ll detect the new hardware and — against all odds if you ask me — figure out that it matches the drivers you’ve already installed. After that you should be right to go.

It worked fine with my ancient FB-310, and it’s something to keep in mind with other hardware, too.