Problems with XFree86 with ATI Radeon 7500

I have installed Knoppix 3.4 with 2.6 kernel, which unlike 2.4, detects my network card. The screen is UXGA (1600x1200) and uses an ATI Radeon 7500 64meg video card. The HD install does not properly detect the video card and defaults to a "basic" card plus a screen with no more than XGA resolution. I have tried changing the XFree86-4 file to include 1600x1200 as default but with disastrous results as it causes the installation to not reboot properly , requiring a complete re-install. Can anyone help?
ps Unlike previous versions of Knoppix the installation does not shutdown properly - ever. Other than that and problem with screen and video detection it is really good.

Try booting up your system with knoppix cd using the cheat code:

Code:

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knoppix screen=1600x1200

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Then find the /etc/X11/XF86Config-4 in the knoppix ramdisk. Copy and replace over this file to where your HD knoppix is install. /mnt/hdaX.

Thank you! I did just that, and it worked just fine! No just the shutdown problem left... :D