IanHall:

I had the same issue with my ABS zForce F2 notebook. I have an SXGA+ LCD display, and the native res is 1400x1050. When I started using Knoppix 3.7, I couldn't go higher than 1024x768 without the screen either wigging out, or splitting/mirroring on me. It was really annoying.

Then I read a cheatcodes section, and have not had the problem yet. When Knoppix boots, press F3 to enter the cheatcodes menu. In the menu type: knoppix screen=[your resolution] depth=32. Only type in 32 for the depth if your machine can handle 32 bit color depth. When the OS finally loads and you make it to your desktop, save a configuration file to your HDD. After that, when you load Knoppix on start up, enter the cheatcodes menu and enter myconfig=scan, and it will load your saved configuration file, and will start up with the correct display.

I'm still running my copy from the CD, so I don't know if it's different from a copy that's installed to a HDD, but I'm sure it is. It's worth a shot though!