Where is the mistake with Fortnite?

I have the epic installer down on my PC and installed. After that, I went for it and installed Fortnite. The game went perfectly, except for the graphics. Everything was slightly reddish and my character stood three times next to each other once in white, red and something like pink. This bug is also there during the game.

I then deleted the epic installer and fortnite and wanted to reload it. I can't download the installer anymore, because I get an error when I open it, that this application is running and can't be fixed or uninstalled…

Maybe it's your PC equipment