Install (if it is not there anymore) the image of one of the kernels Trisquel provides: "linux-image-lowlatency" (that is the one that was installed by default) or "linux-image-generic" or...; Remove the packages provided by linux-libre.fsfla.org (you can easily list them with the "Origin" button in the bottom-left corner of the "Synaptic Package Manager" in the "System Settings"; Optionally, remove the line "deb https://linux-libre.fsfla.org/pub/linux-libre/freesh/ freesh main" from /etc/apt/sources.list with a text editor (here GEdit):
$ gksu gedit /etc/apt/sources.list
I am actually not certain APT will let you remove the kernel you are currently running. If not, reboot on Trisquel's kernel after installing it: at GRUB's menu, choose the "Advanced options" and then Trisquel 7's kernel (version 3.13). If you have not removed GRUB password, first learn it:
$ sudo cat /etc/grub.d/01_PASSWORD It is the number at the very end of the output. The user is "grub".
