weird problem after using xf86config

[Christensen <kriste@sprynet.com>]

I'm very new to Linux--in fact just got the Linux/Windoze (I've learned
to spell it that way!) dual boot to work with LILO.

First I tried XF86Setup, but could not get past the mouse config.  I
have a Microsoft PS2 mouse with wheel, so checked off PS2 and /dev/psaux
(as suggested in the Control-Escape website).  This didn't work, and I
couldn't get past this point in XF86Setup, so I tried xf86config.  It
seemed to go well, and I believe that I entered all the parameters
correctly.  I used SuperProbe to learn that I have an ATI 3D Rage II+
with 2048K of memory and the ATI Mach64 chipset.  Now when I start Linux
I get a colorful screen with the sign-on prompt.  After signing on I get
a solid blue screen, and any key that I hit just "beeps."  The key
sequence Ctl-Alt-Bksp just re-displays the sign-on screen.  All I can do
at this point is turn the power off; even Ctl-Alt-Del won't do anything!

Is there any way to get back to where I was before this mess?

Thanks,
Peter