Update on my scanner situation: I found some software sitting on UMAX's FTP site (which was slow) that let XP be able to use the scanner. But it still scanned garbage (black screens, snow, etc.). Since the software was supposedly the correct version of "VistaScan" (version 3.55)[1] and didn't work, I wasn't going to pay 15 bucks to potentially get the same software that didn't work, and then have to buy a new scanner.
So, we went out and bought a Canon LiDE 30 for 80 bucks, which we've been satisfied with (It's tiiiny... cool). In fact, first thing I did when I was looking at getting the Canon was go to the site and see whether they had drivers available for download from their site. Turns out they had their manual in PDF form and all the drivers you need.
Anyway, the point is that I'll never buy a UMAX product again if I can help it, and I'd recommend you don't either.
Footnotes:
[1]: Note that they even had newer versions, such as 3.75, available from their FTP server. But, even though the software's newer, it doesn't support my scanner, though 3.75 supports a whole boatload of their other scanners. I'm not sure why they'd deliberately stop supporting some of their -- not so old, mind you -- scanners in newer versions of their software, but whatever reason they have (lazyness, broken architecture that they don't want to support in their slightly older scanners anymore) is unacceptible.
Same here, we had a umax scanner that kept on not working. If you wanted to scan you invariably had to unplug and re plug and reboot. Then it started to develop yellow lines, so we just got a new one.