@CaseySJ I did try with CSM enabled but did not make any difference. Same problem. However one thing I tried was to disable the IGPU and connect the 6800 XT to the monitor via DP-DP. The system did not boot at all and kept beeping continuously (according to the meaning of the beeps it seems that it is either a video card error or an AGP error). After investigation I concluded that the system when IGPU is disabled and the 6800XT is connected to the monitor via DP-DP thinks that there is either no video card installed in the system or the system is not connected to any display. But if IGPU is disabled and I connect the 6800 XT to the monitor via HDMI cable, then the system boots fine.I am really starting to think that it is the monitor that is the culprit, at least when using DP to DP cable. The last thing I can try to eliminate any potential issues with the BIOS, the overall system or the 6800 XT is to connect my other more recent monitor if I can get hold of it. If that works then I'll know it is the monitor. If that fails then I don't know what else I can do.