Keef
Maybe try VueScan to use your old scanner ?
I had the same problem with an Acer ScanPrisa 640 U, i.e. no drivers for Vista and my laptop, but have just bought a new desk top machine with Windows 7 and discovered VueScan - and I'm using my existing scanner again. The programme claims to re-activate many old scanners that are still mechanically sound, just need the software.
I think I had to pay around $30. U.S. for the download.
It's not quite do user-friendly as the MiraScan programme that originally came with the scanner, but it does what I want it to.