How to fix a broken account?

[Thomas Sperre]

One of my accounts has been badly bruised some time in the past month. 

The problems I have experienced include:
- at login, something configures my machine with an xrandr -s 1 which is just 
one of my dual displays. This only happens on this single account, but it 
also seems to make Twinview rather erratic when i counter it by giving the 
command xrandr -s 0.
- system settings menyu: i am not able to edit screen set-up
- my katapult stopped working :( it no longer responds to input
- my at shutdown, my applications crash with a sigsegv error message. Almost 
all of them, almost all the time.
- screensaver sometimes starts, other times not, sometimes lock, other times 
not, and sometimes it just seems to freeze the entire system (never actually 
been able to log in and see what is going on, but I ecpect the screen saver 
somehow makes my CPU go to 100%).

I checked that my memory is not corrupted, that is not what creates the 
SIGSEGV error messages when I log out. 

I also created another user, and voila, problems are not there. I think what I 
have to do is somehow restore the troubled account using default values or 
values from the new user account that did not have any trouble.

However, how do I do that?