resolution change does not save???

while logged in as root, in KDE/Knoppix3's Control Center I can go in peripherials, then Display, change the video card, monitor, and resolution to what I think my Laptop uses (S3 Virge MX, TOS, 800x600 16bit is what I'm trying to get), exit out of the Ctrl Center, a dialog box comes up saying my new settings have been saved and I need to restart the desktop environment to see them in effect, I reboot the laptop, get back into KDE, then the Control Center & I see that the video card & monitor settings *are* saved, *but* the resolution keeps changing itself to 600x480 8bit!?!? I've tried this change procedure a few times and it always reverts to 640x480 8bit. BTW, when I first installed Knoppix on the hard drive and went through one of the installation screens where it asked what resolutions my laptop supports, I checked off both 800x600 and 640x480.
Does anyone know why it won't save/use the 800x600 resolution and what steps I need to do for it to start using it?? Also, here's a link to a .pdf of my laptop's specs (a Toshiba 2100CDS): http://t2100cdt.kippona.net/downloads/spec2100cdt.pdf
Thanks in advance!!!