What does this red bar mean and why does Logic crash immediately on startup?

I thought I'd try downloading a free sample instrument for once, but I can see that it was a bad idea. Ever since I downloaded it, Logic Pro now crashes almost right away after opening any session, and now for some reason, the window looks like this.

Would removing the instrument help, and if so, how should I do that? I

feel like I already deleted it, by it's still not working.