Hello David F im my opinion it could the the drivers of the wifi are corrupted this is not a 100% sure that could be the problem but since you say that is a all in one Desktop I really dont trust AIO PC.
You could download this free Legal program that will install 100% updated new drivers (driver park solution)
https://drp.su/index.htm
This could fix your problem with the wifi driver
HOPE THIS SOLVE YOUR PROBLEM :D