Help! Can't boot

[Scientia]

Help! i'm running a PPC iBook 700mhz, and had problems with display brightness keys and suspend. I edited my yaboot.conf and xorg.conf following these, http://ubuntuforums.org/showthread.php?t=798974

image=/boot/vmlinux
	label=Linux
	read-only
	initrd=/boot/initrd.img
	append="nosplash video=radeonfb:1024x768-24@60"

image=/boot/vmlinux.old
	label=old
	read-only
	initrd=/boot/initrd.img.old
	append="nosplash video=radeonfb:1024x768-24@60"

and http://ubuntuforums.org/showthread.php?t=802528 (mchladek's post)
When i restarted, it showed stuff until after the ubuntu loading strip, and then just a blank screen. Any way to revert back to what i had before the xorg.conf changes, or is installing from the cd the only way?

Help! Thanks

[wdaniels]

What did you use to edit xorg.conf? If you did it with gedit then (by default) it would make a backup called xorg.conf~. Editing it by certain other methods also creates a backup - just take a look in /etc/X11 and see what you've got. Otherwise, you could reconfigure X manually using:

sudo dpkg-reconfigure xserver-xorg

Also, since xorg 7.2, apparently if you just delete the xorg.conf file:

sudo rm /etc/X11/xorg.conf

...then restart X (Ctrl-Backspace) it should regenerate a new one as per the defaults.

[Scientia]

I can't boot up the system properly, all i get is a blank screen(black), but i can hear the computer running. Is it possible to do the above from the startup boot menus or using the install cd?

I'm seriously screwed. All help welcome.

Thanks

[wdaniels]

Yes, if you press Ctrl-Alt-F2 (when you have the blank screen) it should switch to a text console.