I have an older computer with an Intel chip that doesn't support WiDi.
However, after setting up a MiraScreen dongle, I am able to right click media files, click "Cast to Device -> <my device>" and it shows up on the TV with no problem.
But if I press Windows + K for instance, it says "Your PC or mobile device doesn't support Miracast, so it can't project wirelessly". So that's pretty dumb. I've searched for a while on that end but I don't think I will be able to go down that path without straight up buying a newer processor.
Is there an application I can use to essentially 'cast my desktop' in the same way that a single media file can be cast? I cannot imagine that something like that doesn't exist.