Well never hurts to try....
You got a point with the waiting.
Here just do the quick and easy fixes, no point of sending it back only to find a quick fix.
So try to clear the BIOS (Take battery out) Unplug power supply, and press the power button a few times and wait 10 minutes, then put battery back in, plug power supply in and try.
If you have one laying around, try a different monitor.
Try re-seating your RAM, make sure the connections on it are solid and firmly on.
Why not try on-board video if you have it on your Motherboard?? That can make a good quick fix to see if the card is the problem.
Try a different wire too....
If all those fail except for the on-board video, then you know your problem