Monitor clicks off

[robcor]

I reformatted and reinstalled Windows XP. The monitor resolution was not right and in the process of trying to correct that I clicked on a box that said something like "not an installed monitor" or something like that. Anyway now when the computer boots up when it gets to the place of loading or recognizing the monitor, the monitor goes blank and so I'm blind and I can't get to the screen to unclick that setting. I tried to boot from the CD but the same thing happens. How do I get around this?

 

[popatim]

boot up into safe mode and correct your monitor settings