Bad Monitor

[Info]

I've changed monitors on a Redhat 8 system.  Went from NEC to Dell (kvm hooked to Win2K machine).  When the Dell monitor is connected to X on the linux box, it blinks it's led's and has a blank screen.  

Its clear I need to change the config.  But I can't use the gnome utility (I suspect it doesn't work anyway) because I can't see the gui.  

Does anyone know what to change to fix this? 

Sign me, Blinky