Digital signal suddenly not working

[kplain]

I have a Hackintosh with a Gigabyte EP35-DS3R MOBO, 2 GB Memory, An NVIDIA 8800GT xxx, or a NVidia 8400GS. Everything has worked great until just recently. I am running 10.5.4 with an intel 6600 quad core processor. Suddenly the last two mornings I have come to the desk and a blank black screen with a flashing green light is all I have. The first day, I shut the system down and rebooted, nothing worked monitor wise. I pulled an old analog 17" monitor out and it booted fine to that and I could see everything. I then tried to reboot to the digital 19" and it went blank again. Eventually I did get it to work. This morning same thing. Only this time I see everything up until the right after the Mac boot screen switches. I believe it is there that it switches to digital. At that point the screen no longer works. I have tried other (digital) monitors that work fine on other macs. But I get the same response from my Hackie. So I switched from the 8800GT xxx to my 8400GS and the issue remains the same. By process of elimination I believe it to be something in the software system side that is causing the issue and that it is not a hardware issue. I did try reinstalling the nvidia software and that did nothing. Any ideas out there?