Paul is getting a Windows CE error in his car. Leo says that Windows used to have a car edition and it sounds like the firmware has become corrupted. Hyundai wants $3,000 to fix the radio. Leo recommends going to another dealer. The trend is to just replace things, rather than try and fix them. Paul should check out iFixIt.com. They may have a fix or a solution, and they are big supporters of the right-to-repair movement.
The chatroom suggests resetting the head unit. Here's a video on YouTube on how to do it.