[aliorhanaydin]

Thanks for your help but it is not working again. In the log file there is no modeline defined.

However I tried something else. I run this command: xmode -x 1440 -y 900 -r 60
then i get modeline for 1440x900 resolution as follows:
Modeline "1440x900" 106.47 1440 1520 1672 1904 900 901 904 932
Then I edited this line to write it in etc/sysconfig Editor. But then again it did not work.
In the meantime, I figured out something new. While booting the suse linux it always use failsafe x.org configuration.
It gives the following message: using failsafe X.Org Configuration /etc/X11/xorg.conf.install
This is the problem i believe it never loads my real configuration.
I thought it might be related with either my keyboard or my mouse. Then i disabled my mouse. Nothing changed. Afterwards, I set my primary keyboard layout as English basic. Then again nothing changed it still loads failsafe config.
I also tried to use krandrtray. But in the krandrtray the only resolution available is 1024x768.
I am desperate...