GPU detected, drivers up to date, not working.

I recently finished building my new PC and had a problem where it would not POST (thread here) the conclusion was that it was the motherboard or CPU so I got a replacement motherboard and the PC booted fine, windows is installed everything looked good. I updated all the drivers and ran a benchmark test with novabench to see how it was rated.When it gets to the GPU test, it gets between 4 and 11 fps before novabench decides that it cant complete the test and stops. I Checked device manager, it says the drivers are up to date and it is working properly. I decided t try another benchmark, used UserBenchMark, similar issue, this time it it skips the GPU test altogether with the message:

WARN: skipping Nvidia GeForce GTX 1080 Ti - Unable to locate attached display.

I have no idea what this means but any help would be greatly appreciated. A few extra things I have noticed:

• I cant change my resolution, it is stuck at 3840 x 2160 (which seems a bit high considering my current issue) which is greyed out.
• In device manager under display adapters it shows not only the GTX 1080 Ti but also Microsoft Basic Display adapter but my current, healthy PC only shows the GPU. I thought maybe this was the cause, maybe it was defaulting to the onboard graphics so I uninstalled it and rebooted and its back.
• I launched World of Warcraft to see how it would perform because it should be able to do ultra settings with ease, it got 1fps.

Any ideas?

1]: [click here