I recently got a copy of Knoppix and am running it off a CD.

At first it wouldn't run at all, giving me a blank screen. I soon discovered I could manually set the screen resolution lower using one of the knoppix startup cheat codes and make it run. I currently am typing
knoppix screen=640x480 vsync=70 depth=16
to make it run. Unfortunately, this resolution is pretty poor, and sometimes applications in the KDE have buttons at the bottom of windows that I thus can't move the mouse to to click on. Those buttons are below the visible screen.
I have an S3 ProSavage DDR graphics card, which is an onboard graphics card. My system has Windows XP installed on it, and the resolution runs much better on XP. (1080 X something if I remember right).
Whenever I try anything higher for screen resolution on the cheat codes, I get a blank screen. Messing with vsync and depth so far hasn't helped. Sometimes the monitor explicitly prints "Out of range" and recommends reading the manual for documentation. I've also tried vga=normal which didn't work.
I'm guessing it's a graphics card problem, but I can't know for sure. Someone else told me it could likewise be a monitor problem for all I know.
Is there any way to fix the problem with the hardware I have, or do I need to buy something else?
Thanks,
qb45man