managing xrandr

[pol]

I have successfully installed kubuntu on my hp tc4200 tablet laptop
but i cannot use xrandr to rotate the screen. After a few attempts, 
the screen has been rotated by 90 deg, i cannot restore the 
normal orientation any more.

Here are my first questions:

In my home dir, the file .rotate-status contains the only character '0'
I that the information the xserver uses to set its orientation?

i have entered several times the command 'xrandr -o normal' both 
as normal user and as 'sudo' user. Is there any difference, depending
on the privileges assigned to the command?

Are there any special settings that xrandr has recorded in the root home
directory? Where is the root home directory?

How to check whether the display ":0.0" is the one used by the xserver?

Restarting the x-server is really needed for orientation change to be applied?

Thank you 

pol