She gave up for now, but mom is receiving this on her computer when attempting to log in: She inputs her password, the Welcome text shows, but then that happens. She has things backed up, but nothing from, like, the past two weeks. Is she screwed or can this be fixed? (@Misty, @Karuta, @Nights☆?) It was fine at lunchtime, but when she shut it down, Firefox was taking a while to close, so she clicked on Force Shutdown. However, I don't think that would cause it, despite the coincidence?
Some videos explaining a fix. Never had this issue so no idea if they work or not, but the method seems legitimate.
Oops. I forgot to edit my post. The video solution didn't work, but my mom pressed F8 during boot-up and performed a system restore, which resolved it. :)