Other half’s school has a bunch of Windows PCs with Movie Maker. Best guess - it’s probably 2007 software. They also have a video camera that saves movies as .mov files (that’s QuickTime, folks). MovieMaker won’t import these files. What’s a good bit of (cheap, free or open source) software to convert the .mov files to (I expect) .wmv files?

I'd suspect .AVI files will do just as well, in which case any of the usual freeware suspects will do the job.

Super C converts most things if you really get stuck.