after the first page i gave up to much of a language unknown to me.
Can you post the text of the file?:
/etc/X11/xorg.conf
This is file that has the settings for your monitors and graphic cards.
If you are going to try to modify it, you should be prepared to undo any changes with a backup file.
You should learn to be comfortable with a plain text shell in case you temporarily mess things up.
Try dropping to a shell by pressing <ctrl><alt><F2> (you get back to your gui screen with <ctrl><alt><F7>
So the first step is making a backup copy of your xorg.conf file like this:
Drop to a shell:
<ctrl><alt><F2>
Then:
login with your name and password
Change directory to where the file is:
$ cd /etc/X11
Make a copy as superuser:
$ sudo cp xorg.conf xorg.conf-old
When you are done, you can press <ctrl><alt><F7> to get back to your desktop.