I have the same issue with a friend's Gateway. He has a new Gateway FX series PC, with the Radeon 6750 card and an old Gateway FPD2020 monitor. Using the DVI connection, I can't get this old monitor to display anything - no signal. I can however use a newer ACER monitor and works just fine using the same DVI cable and connection on the PC. I took the old screen home and it works just fine on my PC.
I set the refresh rate at 60mhz, set the resolution all the way down to 800 x 600, 16 bit - nothing works. Any ideas why this monitor will not show anything on this new Gateway PC?