I don't think if the scanner is old that you will have any luck. Sorry. Only suggestion I have is you might be able to use an XP driver if its run in compatabilty mode. I am not certain if this works but I did read somewhere in the Vista forum of someone who used a hardware driver for XP under Vista in compatability mode and it worked.
Its just a suggestion if no one comes up with a driver and as I said I have no idea if it works or not.
I had the same problem when I moved to XP and with no driver I did eventually have to get a new scanner. Price of progress I suppose but I wasn't happy about it.