If you apply updates in Trisquel and possibly other distributions and find that after rebooting you get a blank / black screen instead of the graphical login window or desktop that you are use to seeing you'll want to follow the directions we created below to fix the problem (you'll see the Trisquel logo initially when it boots and then it goes blank / black):
1. Boot from a live cd
2. Double click home folder on desktop
3. Under device click on the volume that corisponds to your root partition (it's probably the largest)
4. Double click the folder labeled 'etc'
5. Double click on the folder labeled 'default'
6. Open a terminal under menu > accessories > terminal
7. Type 'sudo nano ' and then drag the file called 'grub' from the file manager onto the terminal window (now it'll look something like: sudo nano '/media/trisquel/d63547bd-9c87-25f1-bf2d-6ac78324f3a5/etc/default/grub' )
8. Hit enter and the text editor nano will open the file for editing
9. Find the line that say GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" and change it to:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi=off"
10. Hold the ctrl key down and while doing this tap the o key
11. You will be promoted to save changes (ie file name to write).. hit enter to accept
12. Go to the menu and click power off... reboot the machine