So, since i don't know where this should go (since i have no clue at all to who or exactly where it should go to) i'm going to post it here, and, if an admin wants to move, feel free to do so.
Anyway, starting with my situation.
I decided to upgrade the apps of my system (Using synaptic.)
I'm using Sparky Linux Gameover (the latest version, don't know which one.)
And well, while upgrading my power went out, and the upgrade didn't finished properly. I went back and tried to reboot my pc after my power came back, and there it was, a blank screen with a flashing underscore. It was happening in the same place where the login window should appear. (So the system could boot until one point but it kept trying to load something.)
I was able to get in to the tty console and i did some research on the web, it seems it was something about my display drivers being the wrong ones, and so i went and uninstalled the whole thing (x-server, xorg, nvidia drivers, etc.) and re-installed them again. That did not fixed the issue.
After the next reboot i kept getting the same issue: the blank screen with the blinking underscore.
And so, after researching a little bit more, i ended finding out another solution, it was just starting Debian using another Kernel. I did that, i selected another kernel and the system boot up properly.
The new Kernel i'm using is this one: 3.16.0-4-586
I don't know what was the kernel i was using before, when i found out about i will update this post.
Anyway, so, my issue is, does anyone know what exactly was the problem i had (and that i still have when i try to use my OS using the default kernel.), and if you know what it was, can i have a solution for it? Do you recommend me re-installing my Sparkylinux? what exactly should i do now?
I re-installed completely the 4.x kernels and that fixed the issue. No black screen, no underscore that kept blinking. I was able to log in to my computer again.
Yup, that was the solution: Re-installing the 4.x kernels completely.