Resolution higher than 1024x768 after hdd install

[gitarzysta]

I have installed Knoppix 3.4 using "Beginner style with hardware autodetection".
How can I make screen sizes higher than 1024x768 available for me when using X environment?
The problem is not as simple as it may seem
I manually edited XF86Config-4 (by adding for example 1280x1024 mode) but now I cannot start X at all. It MAY conflict with the built-in autodetection and the later detects 1024x768 as a maximum (at the boot it says: "using modes 1024x768 800x600 640x480").
I have Philips Brillance monitor (1600x1200 @75Hz) and Matrox G400 MAX video card.

[suhanduman]

Hi;
Turn off ddc;
Rem all ModeLine lines under section monitor;