iTunes 12.2 not opening at all on Mac

So my iTunes on my Macbook (Running OSX 10.10.3) updated automatically and now iTunes is refusing to open. I've reinstalled it, restarted my computer, but no luck. I've tried downgrading to an earlier version, but I keep getting an alert in the installer that says the newest version is already installed. Is there a way to get around this, so I can use iTunes again?