Tried to upgrade my older machine (Asus Z77-V Pro, 3770K, dual boot win 8.1 &10) from a GTX 750 ti to the card in the title. The computer has UEFI capability but boots in legacy mode. Wasn't sure if that would be an issue and could not find a definitive answer either online or from EVGA.

I took the plunge anyway.

Short version: Computer boots but is using the Microsoft Basic video driver while the new card is listed as an Unknown Device. Since the card is not recognized, nv drivers will not install (no compatible hardware found) and no amount of prodding on my part did anything to fix this.

Am I hosed or is there hope?

Thanks.

Are you able to test the GPU in another machine whether neighbor, friend or PC shop?  Just to make sure it's not a dud GPU and assuming you've checked all connections and PCIe seating.

GTXJackBauer
Are you able to test the GPU in another machine whether neighbor, friend or PC shop?  Just to make sure it's not a dud GPU and assuming you've checked all connections and PCIe seating.

 
No compatible machine available within a reasonable drive time. The card works to the extent that the Microsoft Basic driver is giving me output via the hdmi port — none of the on-board video ports have a monitor connected. 

AHowes
I think the last guy like this just magically fixed it with either reseating or reseating the power connection to the card.

I will try to install again at some point after I've gathered more info. Pretty sure I had good connections on the first attempt.

SOLUTION
Short version, UEFI/BIOS changes:
1. Changed Primary Graphics to PCIe from Auto. Auto should have been fine, but...
2. Changed boot setting to UEFI for PCIe. I'm not really booting from PCIe per se, but I don't really understand UEFI, so what the hell.

Those two changes made Windows 8 happy as a clam. I previously had uninstalled the 750 Ti and drivers, rebooted to make the UEFI changes and the Nvidia installer had no complaints -- even though Device Manager showed PCI device Yellow Circle Exclamation Point!. Oddly, this is still true after the driver install and correct identification of the card under Display adapters. Someone let me know if I care about this.

Then I booted into Windows 10.

Windows 10 did not care about the UEFI changes, the NV installer could find no compatible hardware. I made one more change (under Secure Boot, changed from Windows UEFI to Other OS). Same result. So, on a whim, I downloaded the NV Studio Driver and it immediately liked what it saw and ran. This is pretty odd since I downloaded the latest Game Ready drivers just before today's session began. I really don't know why the Studio version worked, but it's my preference anyway since I'm all about content creation and not gaming.

Thanks to everyone for their input, I appreciate it.