I am unable to login to my linux desktop since I rebooted earlier today. Did not notice anything strange except firefox crashing a couple of times. It seems like the system is in a login loop. After entering my credentials I get back to the same login screen after a few seconds. When I am going to the console with CTRL+ALT+F1 I get this IO_PAGE_FAULT IO_PAGE_FAULT. I am able to login in to my account in the command line (CTRL+ALT+F1).
You are probably facing two unrelated problems.
For the IO_PAGE_FAULT issue, I will refer to https://askubuntu.com/questions/805008/errors-showing-while-booting-16-04-amd-vi-event-logged-io-page-fault, because that will most probably solve that.
From the rest of the question , I have the impression that you somehow corrupted the desktop environment. One possible solution is to just throw away the environment and start all over again.How that can be done depends a lot on what kind of desktop you use. For example, if you use KDE, you would typically do:
mv ~/.kde ~/.kde.old
If you are root on the system (via sudo probably), you could try:
sudo -s cd /home mv yourlogin yourlogin.old mkdir yourlogin chown yourlogin yourlogin
This is the equivalent of building a new empty house next to your old house. You will need to move your documents, code, images etcetera from the old directory to the new one, but you will not have lost anything, and you should begin with a clean slate.