I guess it has some problems with the screen size , 2 inches of my screen is just blank form either of it's 4 sides as if it's a 10 inch LCD

Presario 2550 / LCD 15"1
current reso=1024*768

I did test other resolutions but the highest which can be set in KDE control center is 1024x768
I guess i should change a couple of things in xorg.conf but I have no idea what those things are?!!