Thank you for the prompt reply. It does appear to be an HP problem, although Microsoft isn't entirely off the hook since they suggest that if their software doesn't implement the multi-file scan feature, it's missing from the hardware. (And in my case, it plainly is available under HP's Solution Center running in Win XP or Vista.)
I installed XP 64 in a dual boot configuration, and run the scanner under that and the rest of my programs under Win 7. Seems silly to have to do that. I have bee looking for other scanning software on the web, but am not convinced of the stuff I found: Hamrick VueScan, JetSoft Art-Scan or LaserSoft SilverFast. Any better ideas for something that works well with prints as well as negatives and slides, but also has separate multi-file scanning capability? Thanks.