Question GPU DVI port problem!

You forgot to mention the make and model of your GPU. Are we to assume that you're working with an Asus 8600GT? You might want to state which version of Windows 10 you're working with. See if using DDU to uninstall your GPU drivers and reinstalling the drivers with the latest revision changes your experience.

Make sure you're on the latest BIOS update for your motherboard. Make and model of the PSU and it's age? Make and model of the displays?
 
You forgot to mention the make and model of your GPU. Are we to assume that you're working with an Asus 8600GT? You might want to state which version of Windows 10 you're working with. See if using DDU to uninstall your GPU drivers and reinstalling the drivers with the latest revision changes your experience.

Make sure you're on the latest BIOS update for your motherboard. Make and model of the PSU and it's age? Make and model of the displays?
You are right, it's an ASUS 8600GT 😉
Actually the issue appears from the beginning of system startup (even on BIOS logo); I tried the gpu on deferent system, and I had the same problem!
I think it's a hardware issue ... what do you think?