Zach, I had a similar problem with my fathers HP 6200c a while ago.
He'd purchased it with his Dell system which came with Windows 95. His system caught a virus (long story.) Anyway, I decided to upgrade to Windows 2000 for him after we got the virus cleaned.
Installed Win2k. HP, USB Scanner didn't work. Hmmm. Checked cables, power, etc. Re-installed. No luck. Took his scanner to my house. Installed it on my Win2k pc. Didn't work.
Tried Windows 98 on his system. No luck. Surfed HP's website. Found "fixes". I modified registry entries, copied over all sorts of files. Didn't work. Ordered the most current install disk from HP. Didn't work.
Called HP's helpdesk. They weren't any help at all. One suggested the USB "port" in the scanner was broken, and that USB wasn't really designed very well.
Okay, for laughs, re-installed Win95. And ran the install, including the USB "patch" from their original disk and it worked like a charm.
In the interim, I'd surfed high and low on the net for forums were I might find other users with similar problems. I found lots of users with problems, some identical to ours, but nobody with a fix.
A few short days after it was working on 95, it started working intermitently.
I was fed up. Scanner wasn't cheap at the time we bought it. Few hundred bucks at least. Supposed to be decent for home use. I'd spent hours and hours uninstalling, re-installing, "patching", calling, surfing, downloading.... I gave up.
Surfed the net for some reviews of Scanners. Wanted to avoid HP at all costs. Read some good reviews on the Epson 1650. On the way home from work, 1 week after Christmas, I bought it for my father.
He can't say enough good things about the Epson. The software that comes with it, he likes about 5,000 times better. The scanned image is better, and it installed as easy as 1-2-3.
I'll never, EVER buy an HP scanner again.
Sorry it's not an answer to your problem.... but your answer may be in another scanner from another manufacturer.