Two ubuntus, one doesn't display

[alex]

My CRT monitor recently went kapoot so I replaced it with a flat panel 
LCD version. 

Previously, both UBUNTUs,(6.06 and 6.10) that I have installed displayed 
properly but now with the LCD monitor, the 6.10 version produces a 
notice "out of frequency" on the screen and nothing else. There doesn't 
seem to be any way to bring up a normal display to adjust its settings.  
The monitor adjustment screen also is not accessible. I also have a 
bootable UBUNTU DVD that does display properly and I can access the two 
other UBUNTUs.

I suspect that the version that shows that notice has screen settings 
set to some frequency that's not acceptable by the LCD monitor.

However, if I press Ctrl, Alt and F1, the screen does display a command 
request in terminal mode.  I suspect that if I could enter the proper 
commands, I could change the screen settings to something that would be 
acceptable to the monitor.

Short of simply removing the UBUNTU that doesn't display, what can I do 
to restore it?