Short answer: It can't be done. Do yourself a favor, don't waste your time.
Long answer: There is no Windows 7 driver for this scanner, and Fujitsu will never make one. The 32-bit Windows Vista driver might or might not work for Win 7, but it has zero chance of working on Win7 64-bit, so don't try.
You can run the scanner in "Windows XP mode". Reports are that this is kludgy at best. I did not try.
If you search, you will find VueScan. The software appears to be legit but does not include any device drivers, so it will not solve your issue. I got suckered into trying the demo, and wasting yet MORE of my time.
But it makes sense. Q: How does any company write 1000+ device drivers for hardware they didn't make? A: They don't. Without a driver, programs like VueScan are dead ducks, no matter what promises they make on their dodgy and overenthusiastic web site.
I wouldn't be in this mess if my old HP Pavilion hadn't given up after 11 years (mainboard died) and cost me an entire day. It looked like the hard drive was failing - which it was, but after 8+ hours of restoring backups to a clone drive, it stopped booting completely due to a mainboard short-circuit. And that was that.
I prepared against this and had a 'spare' Dell Optiplex 320 in the wings. So I tried to install the Fujitsu driver and Scandall32 on it.
But no matter what I do, I can't get the installation to "stick". Every time the scanner hibernates or I reboot, Windows XP "loses" the scanner. It takes about 3-4 reinstalls to get it back up, and then it'll get lost again. I tried various installation patterns, using a USB hub (seen that work before, on a UPS) and even a new USB cable even though I knew the old one was fine. No luck.
This is after figuring out how to bypass no less than THREE passwords on this ex-workplace Dell. I got in, but then this. Another entire day wasted.
I wanted to try a clean Windows install on the Optiplex, but if there is a factory restore option, I can't find it. Ctrl-F11 seems to be the correct shortcut, but it does nada, and apparently the 320 has no such recovery option. I don't have the original media discs (of course) and I'm really not up to a complete fresh XP install.
I wouldn't be so worked up if I knew that I could get a replacement for my trusty old fi-4220c. But I've read some reports that the nearest replacement that has both ADF and flatbed - the fi-7260 - comes with truly awful Paperstream Capture / Paperstream IP software. Both appear to be attempts at "document management" applications, which are the last thing I want. I want the damn thing to scan to PDF and put the PDF where I want it. Maybe OCR it, but that's optional. And that is all.
Unfortunately setting up separate flatbed and ADF scanners is quite awkward for me. My current workstation was partially built with the truly humungous fi-4220c in mind. Maybe some kind of stand will do it.
I'll have to see if the ScanSnap Manager will do what I want, I suppose. Early indications are that it will, as long as it's not going to force me to put everything into a fixed destination folder, or force me to do a different profile for every possible destination. That's just not going to work.
Silver lining is that a newer USB 3.0 scanner will be so much faster than the old 4220c - and hopefully better at ADF, too. I have to admit that 4220c jammed many more times than I would like. A glorious workhorse, but by no means perfect.
If anyone has suggestions for a better fi-4220c replacement than the fi-7260, I'm all ears. But keep in mind I need a solution that includes both ADF and flatbed - though not necessarily in a single integrated device.