I used hospital wifi and it took over my pc and keeps sending popups to okay their site and password. How do I make it go away?

Your didn't say anything yet.

have you tried going into your network settings and remove the network from there?

In Windows 10:

   Click on the Start button and select the Settings app.
   Click on Network & Internet.
   Click on Wi-Fi.
   Click on Manage Wi-Fi settings.
   Under Manage known networks, click on the network you want to remove.
   Click on Forget.