it won't let me use the launcher

a few days ago I was trying to play crazy craft on my pc and my world wasn't loading/working so I tried to play a different mod pack sky factory but every time I opened the launcher it was the crazy craft mod pack so I exited everything then I shut off my pc and turned it back on and I tried to open the launcher again and it wasn't opening so I went on youtube and looked up how to fix it and I did everything it said and it still wasn't landing so I then troubleshot it and it said something like incompatible file fixed and then I went out of that and I see a shield next to the launcher icon on my desktop and thought nothing of it at first so I try to open it again something came up and said are you sure you want this to make changes to your device I clicked  ok and the screen went black and turned back on and it changes my refashion and everything was zoomed in and it didn't even open the launcher