Can you see any bent or missing pins in the CRT monitors plug end? There should be 15 I think for a VGA analog connection. Do you have a friend who can bring a laptop or PC over to test it on another PC with a VGA connector? Perhaps the CRT monitor is only able to produce a specific resolution, try looking up the monitors specifications on the manufacturers site. If the company doesn't exist anymore try putting the make and model in your search along with "specifications". There are sites out there that keep that info after a company is no longer. Did you look through the bios? Sometimes with on-board video they put stuff in there.