It's a long shot but see if you can get the ScanGear software for XP to install before connecting the driver
http://files.canon-europe.com/files/soft6108/software/S2901enx.exeVista will complain and won't install the driver correctly but Windows should correctly identify the scanner when it's connected then Vista can see if can find a compatible driver on the Web.
This won't work for W7 and Microsoft don't list this model in their comptibility lists for Vista or W7 so replacement does look likely :(