Thanks, everyone
The combination did the job, but I suspect the tipping point was turning the wireless on. (I've been avoiding those annoying "special offers" from Amazon, having discovered that turning the wireless off and doing a re-start eliminated them.)
Now to install 5.3.3. I'll advise if any issues arise, although Mort's experience seems benign. (BTW, the comment that it is a complete, new OS was taken from an article I'd read earlier today before coming across this very helpful forum.
Hope I can offer some assistance in the near future.
Cheers, Garrett