Glitch problem (just after opening some DjVu files)

[lacabaca]

Hey guys


My lubuntu graphic system appears to get some malaise after i've opened some DjVu files, which, for some reason, use to be quite taxing graphically and memory-wise to the system(especially when compared to PDF files).


After this problem happened i restarted the machine(twice), but to my surprise, it kept this way.


When the system was shutting down, it showed repeatedly and extensively some strange "ply mouth" command-line during the process of shutting.


So, does anyone have an idea on what could be the problem?


Thx!


PS: (a) Glitch problem pics - https://imgur.com/a/yJ70Ld8
(b) Normal graphics, before the problem occurred (for comparison) - https://imgur.com/a/62XgEZV
Edit: PS: nope, It's doesnt seem to be a hardware problem at all. At least that's what conclude since the BIOS starts normally graphics-wise(so bios and hardware are apparently ok). It manifests only from the login phase onwards.

[lacabaca]

Ow, another thing: I've using "xinput" recently. Could this be the problem?

Please, help me! I don't wanna format or uninstall it now!

And I have to say: this is my first "long" experience with the system and I really expected it was much more reliable.