What a thorny issue George! It sounds like there is some incompatibility
between this piece of hardware and something that has been changed between
Trisquel 7 and 8. To confirm this, have you tried using a live USB made with
a different version of Trisquel (eg 7)? Also have you checked for a bug filed
against this issue?
https://trisquel.info/en/project/issues/trisquel
Trisquel 7 is supported for another year, so my advice would be to use 7 to
get this PC back into a working state, and help the Trisquel devs figure out
a fix, then put out an updated .ISO before the end of the year.
