Change to character mode?

[Robert A]

I have a Red Hat Fedora installation that was setup with the incorrect
screen resolution.
My ATI Mach64 (whoohoo) card is easily capable of 1024x768.
I made the mistake (?) of selecting a Generic screen of that resolution.
The GUI login screen comes up as an incomprehensible fluttering screen as
though the horizontal hold was way, way off!

I tried CTRL-X to go to character mode to no avail -
I'm currently at the Linux rescue prompt to try to figure out how to change
the resolution to 800x600, or force the system to boot into character.

I did an update install as well, forcing 800x600 and it still looks like the
horizontal hold is busted - can't see anything like it's in an opposite
interlace mode.

Any experience or ideas are greatly appreciated!

Robert Achmann.