GUI does not load after monitor is changed

["Allyn Baskerville" <allynb adsne com>]

I suspect this has been asked several times as it's happened to me a couple of times, but I didn't see the solution in the archives. 
I have RH RC2 installed on an old Compaq 800 ProLiant. After the machine was built, I moved it to a rack with a KVM and a different 
monitor installed. I could tell the GUI keeps trying to load but fails. I suspect the machine doesn't recognize the monitor. I tried 
to change /etc/X11/XF86config, but it hasn't helped at this point. Do I need to try something else, or should this file be the 
culprit? Thanks - Allyn