The next time it happens, it would help if you could take a snapshot of the screen so that we can see what's going on at the time. Context is a lot, if not everything, in diagnosing problems like this one. I know that techies always want to see a cursed screenshot; but, there's actually method in the madness. I help a lot of relatives and the most successful ones are either when I get a screenshot or, even better, I am logged into their PCs remotely using a product such as TeamViewer.
P.S. Thanks for the kite compliment! If I decide to stick with this hobby (it is intensely more challenging than I first imagined), I have three more I want to add: Solus-UL, Ocius-SUL, and I-Nak.