I will run the X3 installer again, after which I will run X3e.
I went through all of the registry place where SONARPDR.exe appeared, and did not find anything there that looked like it would point X2 to open midi files, but that's what happens on my machine, so there must be some other mechanism in place - OR I missed it. I of course found lots of mentions of X2 and X3 in the registry, but nothing that looked like a place to tweak successfully, so, as noted above, I will just run the X3 and X3a program installers only, to set midi files to open with X3e.
Any how - as I am typing this, my brain keeps shutting down, so first will come a long nap.
Bob Bone