updates messed up all my configurations

anyone?

Well cinnamon is not the standard desktop of Trisquel. So it is not very likely that anyone is experiencing your issues.

From my experiences you now have two possible approaches (given you have another working (!) PC for searching the www):
1) Look through all logs in the shell after boot and try tho find the possible cause,
or (less time consuming)
2) Create a backup of your personal data and re-install the system. One can waste an incredible amount of time to fix a screwed up system. Possibly you get it to work again but often strange side effects stay.

After the last lot of updates (some of which were cinnamon updates) I lost touchpad functions, browser functions, all sorts of mess. I reinstalled Trisquel, set everything up, installed Cinnamon and it was the same. So, I reinstalled Trisquel and went straight for the Mate desktop. All is OK again.

I'm not technical enough to know why or how to invesitage and with the choice of alternative desktops, Mate is the easiest option (I prefer it to Cinnamon anyway).
I just installed Mate per the instructions on their webpage for Ubuntu 12.04

thanks!