Just getting started here, with no knowledge of any Linux commands.... so please give any advice in plain English!!!

Booted with the parameters "knoppix26 screen=1600x1200" (have an ATI Radeon 9600 card and a Dell 20" LCD). The Dell is recognized, also that the card is ATI, and that the resolutions from 1600x1200 down to VGA are available.
BUT, under the control center settings, the resolution is STILL limited to 1024x768 refresh rate at 75 Hz (not changeable) and using the "ctrl-alt-however_it_ goes" combo suggested in other threads,this just sycles me through 2 totally scrambled screens and then back to the same 1024x768 one again...

Otherwise I find the whole concept and look and feel very cool, so I would really like to get it working..... any help much appreciated.