I have a problem with my ATI Radeon HD 2600 XT graphic card

Hi. i have a ATI Radeon HD 2600 XT graphic card. when I install its driver on openSUSE 11 ( or any other linux) , whatever I change my display resolutian to 1280x1024 when I restart the pc, system changes its resolution to 1600x1200.

How can I fix this problem?

Try rebooting in text mode (runlevel 3) and typing sax2 (uhm… or was it sax2 -r)? That should hopefully (re)configure your screen settings.