Welcome to GNU/Linux. Some call it just "Linux" by mistake. Have you heard
about GNU?
https://www.gnu.org/gnu/gnu-users-never-heard-of-gnu.html
Searching: https://duckduckgo.com/?q=ubuntu+checking+battery+state&t=trisquel
This is some problem with the display manager; if you are using GNOME
(default Trisquel configuration), it is the GDM; if KDE (on Triskel edition
or after installing it), KDM.
GNOME is a GNU project: https://gnu.org/software/gnome/ ; KDE is not. Neither
belongs to Linux, which is a kernel and not an operating system, as GNU is.
You probably should reinstall your Display Manager:
$ sudo apt-get install --reinstall gdm
OR
$ sudo apt-get install --reinstall kdm
. There is a similar command "aptitude reinstall", though I have no clue
about the differences between them, if there is any.
Welcome to Trisquel :-)
