Hi again Magic Banana.
THE PROBLEM I MENTIONED ABOVE MIGHT NOT MATTER NOW BECAUSE:
1. Yesterday Sept.11, I bought an older & smaller monitor, and Trisquel's
default resolution setting (1024x768 & 76 Hz) - which I still can't change -
DOES work alright, as far as I can tell at this point.
2. There may or may not be some problem with by motherboard's built in video.
Hmm... just realized, so many Trisquel users have tried to help with this
that I
I should put this as a reply to my own original request for help... there
will be more info there if you're interested.