Pulled 7200 RPM HDD (and the 240 GB SSD) out of Desktop A and installed the 500GB SSD.
While I was inside, I removed the excess cabling and just cleaned things up in general. Went to Tim the Computer Guy's shop and traded my 4.5' monitor cable for a 6' one so I could get my monitors into the position I wanted them. I also removed the wired Internet cable. So far, Internet works just fine; at least Windows installed.
Installation of Build 14291 went smoothly and so did Office 365 64 bit.
Since I had so many freeze-ups with Build 14279, I'm not going to install Firefox yet. Hopefully I won't get frozen with this build, but we'll see. At least FF is out of the mix.
For now I'm using the IE with a Mohawk; I'll give it a chance to see if there's any improvement.
One thing at a time . . .
Edit: Just to test to see if Edge behaves itself when I Edit my post. So far, it did, but what's strange to me is that instead of just bolding things, I get the b and /b (in brackets. Which might be OK, except it requires extra keystrokes; I'm fast enough, but not everyone has spent their life using a typewriter and then a keyboard.
Oh, and I went in to Settings and put myself back on the fast track. And now I'm going to change my time zone.