Windows 10: What is wrong with my VIDEO Card ??

You can emulate some features in software but nowhere near as fast as done with hardware.
https://www.geforce.co.uk/hardware/t...supported-gpus
https://www.geforce.co.uk/hardware/t...supported-gpus

 

And if you look at some other YouTube videos, you'll find people who have gotten (non-Dell) GTX 1070 cards to work. (I didn't check whether a PSU upgrade was required. Maybe just an adapter: one example has a single 8 pin PCI-E power connector.)

If you're serious about playing with the "mixed reality" stuff, I suggest:

With your existing graphics card in place, do the BIOS update to A10. (It's not 100% safe, but it's unlikely to brick the PC, especially because it's a Dell.)

Buy a compatible graphics card from a place that has a good return policy, in case you can't get it to work.

(Optional*Smile Get a friend who is more experienced with PC hardware to help you get it up and running.

 

I purchased the "like new" GeForce GTX 960 2GB GDDR5 OEM DELL OH4P1K from eBay. This was an OPTIONAL Video Card (upgrade) for the Dell XPS-8700, thus fully compatible with stock Dell 460 W PS. This card used one of the 8 pin connectors that were unused from the PS. Believe it or not, uses the exact same NVIDIA driver as the GT720 did, which is about two weeks old. Has one Fan on this "new" card. I'm not a Gamer, but just wanted a "better" GPU and this 960 2GB works quite a bit better than the card I had.
Plus only $80, free shipping (came in 3 days) My "problem" is SOLVED !!

 

That looks like a pretty good price.

I would have uninstalled the nVidia drivers, swapped cards, and then installed the latest drivers. Just to be safe. Easy, but probably unnecessary.

 

Took your advice..................just completely UNINSTALLED ALL NVIDIA programs and drivers (six), rebooted and installed NVIDIA GeForce GTX 960 programs from scratch.