I just tested some Trisquel discs on the same laptop.
The version that didn't boot was 6.0. I was able to boot up 6.0.1 just fine.
Trisquel 7 will only boot if you pass a "forcepae" boot parameter.
To do that, press F6 after choosing your language on the CD boot screen.
Press escape, and you will notice the boot parameter text appear near the
bottom of the screen. Select the option you want to boot into (live, install,
etc.) Move the cursor to the left of the double-dash (--) and add "forcepae"
to make the end of the parameters look like this: previousparameter forcepae
--
Press enter, and it should start booting.
