Killed my computer after upgrading

Okay, so I got a message to upgrade to 16.04. I hit OK and it went through the process. Upon restart, there was no cursor (I think it was invisible). I read somewhere to switch from lightgdm to gdm, and so I did. And this did bring the cursor back. However, upon restart, I get to the Ubuntu screen with the dots and it just sits. Nothing. I would change it back, but I have no idea how to get back into the computer to even do it. Worse comes to worse I can always just do a clean install. I don't have any important files on there, but if there's an easy fix I'd love to know and save the trouble. Thanks.