I can now report complete success! Thank to your help and some
experimentation (and lots of reinstalls), I finally nailed down exactly what
I needed to do in order to get Trisquel to install and boot on my system with
no problems.
1. Boot up Live CD. "Try Trisquel without Installing", with the F6 "acpi=off"
option enabled.
2. Use System Settings -> GParted to partition and format a logical partition
for Trisquel.
3. Install Trisquel to this partition, with no separate /boot or /home
partitions.
4. Before rebooting, root the new Trisquel file system as described here:
http://askubuntu.com/questions/145241/how-do-i-run-update-grub-from-a-livecd.
5. Update Trisquel's GRUB file in the terminal with "sudo nano
/etc/default/grub". Add acpi=off to GRUB_CMDLINE_LINUX, save and close, and
update grub with "sudo update-grub".
6. Unmount Trisquel's file system and reboot into the new Trisquel
installation.
7. Run System Settings -> Update Manager and reboot as instructed.
8. After rebooting, run System Settings -> Synaptic Manager and install
"linux-generic-lts-belenos". Update GRUB. Reboot and ensure that that the
GRUB Menu indicates that Trisquel is now using the 3.5 kernel (I did this
mostly to make sure that when I updated to the latest kernel, I would
actually boot into it).
7. Log in to Trisquel, and follow the instructions at
"https://trisquel.info/en/wiki/update-linux-libre-kernel"; to update to the
latest kernel.
8. IMPORTANT: Re-edit the GRUB file and REMOVE "acpi=off". I found that, even
after updating my linux kernel, if I still ran with acpi=off, Trisquel would
boot into Fallback mode with the VESA driver, severely distoring my display.
9. Update GRUB again, then reboot.
10. Enjoy a fully functional, booting, updated and properly-dsiplaying
Trisquel 6.0 system!
