Disabled graphics card detected and used - blank screen

[steevieb]

I am trying to boot a live-cd (of dyne:bolic 2.5) although I have had this problem before with other distros.
The problem i have is that I have a 4mb ATI Rage built-in graphics card (disabled by dip switch)
and a 128 mb PCI graphics card (Radeon 9250) that I want to use.
However, on bootup, the Rage card is used and the screen is blank.
How can I force the use of the Radeon?
Is there an xvesa option, or a xorg wizard, like in puppy?
I can get to a root login with Ctrl+Alt+Backspace. Is there a text editor to alter xorg.conf?

PC is a 600mhz Compaq Proliant ML350 1280mb ram

[peteh]

I disabled my onboard graphics in the bios.