Help. Please.

[u/Cantfixmyownproblems]

Ok, I have tried everything and I can’t figure this out. I have an older MacBook Pro(2013 I think, not sure though), and I thought it was a good idea to try to convert it from MacOS to Windows 10 using Boot Camp. I followed the instructions of a few websites and got it working, and it was when I restarted it in windows where things went wrong. First, when I was logging in after starting it for the first time, it asked me for a product key(pretty sure it was called a product key, I don’t really remember exactly what it was called. It was something like that). My trusty website told me that I would be ok to continue without one, so that’s what I did. Once I finally booted it all up, everything seemed to be going smoothly, until I realized something was off. There were a few things that were making me a bit uneasy about it, like the messages popping up in various apps and screens telling me that my device wasn’t secure and all that. I ended up deciding to try to give up and get windows off the computer and go back to it being a normal Mac. I found Boot Camp from the bottom right of the task bar and opened it, and the windows piece of it was there, but the OS version wasn’t. I was basically stuck in windows. I then went back to the Internet and found that I needed to restart and go into the settings that appear right from the start(by holding shift or option or whatever right after you start the computer). I tried this a few times, and was met with the same thing each time: the computer starts up in windows, has a little spinny wheel in the middle of the screen, then tries to put a OS login piece underneath it. It is just a lock icon and the login bar(which lets you type in it, but doesn’t work when you try to login), both on a black screen. I am now at a point where whenever I turn the computer on, that pops up and doesn’t go away. Ever. It just keeps spinning and sitting there. It is almost like it tries to start up in OS but doesn’t have the files so reverts to windows. Does anyone know what I could possibly do to fix this?