My monitor is displaying "No signal" message

[StuneDX]

So I've been using my current rig for about 2 months now since I've changed my old PSU with a new one.
Just about 2 days ago when I tried booting up my pc the monitor wouldn't display any image asking for me to check the connection. Ever since I've been trying all the tricks in the book.
One of them did work, but in the I cut my infected arm of kind of way. I had removed my GPU and all of a suddenly started working. But I came to the conclusion that it actually isn't a faulty GPU because I've tried a couple other lower end GPUs. Also because they were lower end, they would've been easier on the PSU so it can't be it either.
The PC works with all the RAM in so that can't be it either.
And there is no indication that the CPU is the problem so my not so vast experience I would say it ain't it either.

The last culprit is the mother board but I want to see if any of you guys believe otherwise before I turn to a local professional.

Things I've tried:
New cables
New Sockets
New PCI slots
New CMOS battery alongside a reset
New monitor
Shuffled the ram and removed it 1 by 1
Tried 4 GPUs nVidia GTX 760/650 x2/260
I also made sure that all cables are plugged in
Just as P.S. I don't have an internal speaker

Setup that worked not 2 days ago
CPU: Intel quad core 3.2GHz (3-4 years old)
GPU: nVidia GTX 760 (2 years)
RAM: 16 gb (4xemptyx4x8) (varies from 3 to just 4 months)
Motherboard: Gigabyte H77M-D3h (3-4 years old)
PSU: Not sure (2 months old)
Windows: 7 Ultimate (it is missing some optional updates)

Setup that currently "works"
CPU: Intel quad core 3.2GHz (3-4 years old)
RAM: 16 gb (4xemptyx4x8) (varies from 3 to just 4 months)
Motherboard: Gigabyte H77M-D3h (3-4 years old)
PSU: Not sure (2 months old)
Windows: 7 Ultimate (it is missing some optional updates)
GPU: N/A incorporated

 

[Cycloid Torus]

I hope I followed the narrative correctly. No GPUs work on this motherboard, but all GPUs work on another motherboard (including ones which do not require 6-pin power, to prove it isn't the power to the 6-pin connector from your new PSU) but the internal video does work. When using internal video, everything else works just fine (eliminating RAM, CPU, drives, the same video cable, monitor).

That would lead me to believe it is the motherboard - though it could be as simple as a short to the case from the back of the motherboard (lose any screws lately?) - or a cracked solder joint - or stuff in the PCI-e slot.

Consider pulling system apart and examining motherboard - magnification and strong light. Since it is out of case, also consider a test rebuild out of the case ( select 2nd row far left column)