Hello,
I just started using Scrivener, and turned it off for the first time today (my firefox was acting buggy and I restarted whole computer) and now it will turn on (sort of) but it won’t quit unless I use force quit, and it won’t open my document. At all. I double click on it, I drag it into scrivener, I open from File menu: it will not open. Help.
Welcome to the forum. I’m sorry that you’re having problems.
If I were you, the first thing I’d do is re-download and re-install the software. Perhaps your buggy Firefox caused the download to be incomplete?
So do you mean uninstall what I have and then reinstall? I am worried that will destroy what I have on the existing file, but I guess it doesn’t have to.
I will try.
Generally speaking it is impossible to destroy your documents when messing with software alone. The two are kept completely separate for that very important reason, among others. You could move Scrivener to the Trash, empty it, reboot, and not lose a single piece of your work. Granted, you wouldn’t be able to open the projects directly until you reinstalled Scrivener. 
On that topic though, have you tried using any other projects yet? If they don’t crash, there probably isn’t any need to reinstall. Just open Scrivener with the Shift key held down (so it doesn’t load anything automatically), create a new project with the File menu (just the tutorial is fine) as a test, and see if it runs fine with that project.
I uninstalled and reinstalled before I saw that, and it opened with “Last time Scrivener crashed when you used it” and I sent in an error report and I very much hope that nothing bad will happen anymore.