It was indeed in thumbnail view, for a folder with over 10000 photos. I thought I was pretty patient with it though, before attempting to load up the Task Manager, though as I said, it refused to come up, and my patience eventually ran out and I forcibly shut it down. After doing so twice I was afraid I messed up Explorer or some other key file.
I tried the F8-at-startup thing and eventually (though not the first few times) it gave me a chance to try the last known configuration that worked. It was still really slow to boot up but eventually it started up ScanDisk on its own and deleted some bad entries. It started up fine again. I made a Restore Point just in case - for some reason on that particular computer I didn't have any previous... odd... and rebooted again. It was really slow and I was afraid I missed my chance to get work done on it but it eventually got back to where it should.
So, it does work, but it might have extended boot-up time now. Like instead of a couple minutes, over ten. I wonder if I need to defrag it or consider getting a new hard drive specifically for the OS. If the two times it worked last night was only a fluke, I should look for a Vista disc, not just to reinstall, but to do a particular Vista Black Screen of Death fix that a friend mentioned.
Thanks for the help, everyone.