I'm trying to reinstall an old server with Ubuntu 12.10 (it was previously on 12.04 I think, but had accumulated a lot of rubbish and a fresh install was the way to go).
When I boot the LiveCD, at the point that (I believe) lightdm starts, I get "Signal out of range" on my monitor and can't get any further.
I have tried various boot options (nomodeset, fb=false) without luck. I've also tried creating an xorg.conf file manually from the terminal and restarting lightdm - that has got me closer but I don't know my way around xorg.conf well enough to get this to work. (I copied xorg.conf.fallback to xorg.conf and added VertRefresh and HorizSync parameters, which got me a low resolution (800x600?) display but the mouse was all over the place and I managed to break it in the end so had to (hard) reset, losing my changes).
What is the "correct" way to fix this? Is there a way to tell Xorg to dump its current settings to an xorg.conf file so that I can tweak it? What's a good "default" xorg.conf file that should work? Or a minimal one that might get me 1280x1024@75Hz (fglrx as the driver from memory).