AHA!! It WAS Cubistry!! And I hadn't played it lately (I've been on my first jag of Words with Friends.. or in my case, Words with Total Strangers, but we keep playing again) but yes, it was updating, per the notification, I saw later. And no I didn't ask it to update. hmm
The calculator apps hadn't been downloaded or re-downloaded since the de-register/re-register.
So. Cubistry seems to be the culprit!
However, the browser was displaying solid black for DAYS, even though the icon on the carousel would show a miniature of the page/site that was blacked out. I was peeved because I like to be able to use GasBuddy, or click on links to caringbridge from email, .. on the Fire. No Smart Phone.
Anyway, mystery solved, at least for the total freeze.