Why would you not connect the 2 8pin power lines to the 1080?? No idea if that's just s typo or what? Cause normally if one did so the computer would beep (if speaker is connected) and would not post.

So, with the card half inserted into the motherboard, it didn't boot.  Without the card installed, it booted fine.  Then, with the card installed and no external power connectors connected to the card, it booted fine.  And now, what is the question?  Did you ever finish the last piece of the puzzle?  That being, of course, connecting the external power connectors to the card.
 
So far, all you have provided us is a series of user errors and nothing further.

AHowes
Why would you not connect the 2 8pin power lines to the 1080?? No idea if that's just s typo or what? Cause normally if one did so the computer would beep (if speaker is connected) and would not post.

Well I was out of ideas and the PC won't boot at all if the power connectors are plugged into the GPU. (I thought that was peculiar myself)
 

AHowes
If something happend to the card while not inserted fully, and now it's not working you should inspect the pci-e slot pins on the card and port on the mb. Check the gold pins on the card and look for black marks from a short. Clean both sides with a dry paper towel and or rubbing alcohol if needed.. to clean any crap.

Shine a flash light into the pci-e slot and check for any noticeable damage caused by a short.. again burn/melting.. black crap.

If there's nothing then good.

Try the card again and make sure with a flash light if needed that the card is fully inserted and not being hung up on the i/o plate on the card.. sometimes it gets hung up on the case card slot cover.

Plug in the power connectors!

Upon looking much closer with a flashlight, I notice that one of the power connectors seems to have come apart in some fashion. Does this mean I need to attempt to swap out the piece that connects to the graphics card, I assume so. Thank you all for the assistance in advance! 

Cool GTX
Slide that wire back in to the block, if it does not lock in place - do not use it, just wrap with some electrical tape to keep wire in place inside of plasic to prevent shorting.
 
You PSU should have had more PCIe power cords - use one of the other ones

I appreciate the help, through some more testing it appears one of the VGA power cables has stopped working for whatever reason. Looks like I'll be making a microcenter run today, thanks everybody for the assistance. 

Have new (1 NEW)EVGA Geforce GTX 1080 FTW Gaming ACX 3.0, 8GB that will replace current installed (#2 current)EVGA Nvidia Geforce GTX 760. How should I go about the uninstallation of card #2 drivers /software for installation of the new card?  Requested: Please help with step by step info so process (removal and installation ) completes with ease / no issues hoped.
Thank You and Much appreciated 

SDDG27
Have new (1 NEW)EVGA Geforce GTX 1080 FTW Gaming ACX 3.0, 8GB that will replace current installed (#2 current)EVGA Nvidia Geforce GTX 760. How should I go about the uninstallation of card #2 drivers /software for installation of the new card?  Requested: Please help with step by step info so process (removal and installation ) completes with ease / no issues hoped.
Thank You and Much appreciated 

Should of started a new thread for that.

What you want to use is a program called DDU. Display driver uninstaller. Grab it here and install. https://www.wagnardsoft.c...c0381304a6782424216049

Then grab the newest drivers for your card and win is at www.nvidia.com.

Now you want to go into safe mode first before running DDU. Google it for your specific windows version.

Once in safe mode open up ddu and select uninstall and shut down for installing new card.

Once it's done and powered d oen your pc, flip the switch off on your power supply. Plug the plug out from the backside of the psu. And hold the power button in on the pc for 20-30 secs to drain all power from the system.

Now remove the side panel from your case and remove the power connections from the graphics card and the monitor cable from the backside of your card. Unscrew the card from the case and remove it.

Install the new card making sure it's fully seated in the pci-e port. Plug in the power connections.

Plug the psu cord back in and flip the switch on the pay to on end power up the pc.

Once in windows install the nvidia drivers you downloaded.

Be smart to reboot once it's all done.

Make sure to grab the newest version of pxoc from evga to monitor your new card and change the fan profile to your liking.

Test it out with your favorite games!

:/ let me guess it's the same pin on the card side from the broken pin on the 8 pin power connector.

Meaning the male pin on the card side is either toast or it's been pushed out on the connector or broken solder joint on the card.

If any of that happend evga will notice it.

If you shine a light in that 8 pin connector, is the male pins all even or is there one pushed in?

If it is pushed in, you would need to remove the cooler to get access to that pin to push it back into the connector. If the solder around the pin is loose one would need to resolver it.. if the pad the solder is connected to is now ripped from the card one would need to trace the connection on the pcb and solder a wire to a new spot to the pin.

If there's no bent/pushed out pin, better hope there's no physical damage to the card so they rma it.

AHowes
Also what happends if you swap the 8 pin psu connection on the left side. Will it power up?? If not then maybe the 8 pin connection is bad from the psu end. If so check to see if there's another gpu connection to the psu to use other then the one.

I've tried swapping the cable over, using different cables, everything short of kissing it and sweet-talking it. But no luck yet. Gonna try your other advice when I get home. Appreciate your persistence today!

Sucks.. hope it all works out. Guess something happened to that card.. was it something you did? Prob not as it was working all along till one morning. That pin issue may of just happened while you were uninstalling and reinstalling the power cables to get it to work again.
 
Evga will take care of you!