well after a lot of searching on Google, I have found a solution to this issue:
editing xorg.conf and adding to section "Device" as follows:
Option "ConnectedMonitor" "CRT-1"
Some times flicks or blinks for a second but at least now it works! I guess the problem is related to the identification between my screen (LG 1953S 19" monitor) and my GPU Nvidia 8400GS PCI. I am not a technician but it is hard to believe that anyone in Nvidia or any Linux distro has not found a solution to the problem, thousand of users with the same unsolved issue.
well after a lot of searching on Google, I have found a solution to this issue:
editing xorg.conf and adding to section "Device" as follows:
Option "ConnectedMonitor" "CRT-1"
Some times flicks or blinks for a second but at least now it works! I guess the problem is related to the identification between my screen (LG 1953S 19" monitor) and my GPU Nvidia 8400GS PCI. I am not a technician but it is hard to believe that anyone in Nvidia or any Linux distro has not found a solution to the problem, thousand of users with the same unsolved issue.