Multiple system errors, wireless card and trouble booting  

I got up this morning to my PC having issues. The wireless card I was using was disabled. I installed it a few months ago because I was getting interference and therefore a very slow internet connection in the 2.4 ghz band in a multi unit building and my old card doesn't carry 5 ghz signals. I just left the old card in and disabled it under settings-wifi and told it to prefer the 5 ghz band network. Using the device manager didn't help get it working so I restart thinking that'll help. Then the computer stalls on the windows loading screen (after bios and before login prompt) so I hit the restart button, it sends me to diagnostics and just restarts to stall in the same place. I was able to start in safe mode with networking. I'm on the old network which is pretty bad but was able to find a download for the driver for the new network card, which windows tells me is already the best available and I can't enable it.

What can I do to fix the booting issue, I wasn't given any error codes? What do I need to do to fix the new wireless card?

Leaving unused hardware connected is not good practice.If you can,remove both cards and ensure the drivers are also removed.
Then check Reliability History for entries concerning the problem,lines 1&2 in---view tech details---give searchable information.
Next run---sfc /scannow---and---dism /online /cleanup-image /resteorehealth---to clear up any file corruption
Reinstall the new card and allow Windows to install the driver and see if that makes any difference.

The computer boot properly after umpteen resets and worked for no explainable reason, but I'm done with trying to get wireless working and ordered enough cat5 to hook it into the modem directly. The laptop and tablet work well enough over wifi so that's the only change I'm making.