How to fix these problems?

So I opened Unity today and saw many things wrong, the editor kept on freezing and the collaboration is gone, even though collaboration is enabled. On top of all of this, all of my code has an error saying "No MonoBehavior scripts in the file, or their names do not match the file name." I have searched everywhere but cannot find any solutions, please help. The collaboration button is gone and I have Uninstalled and Reinstalled Unity. I am using version 2019.2.8f1. Please help! Thank you in advance!