The Game Keeps Crashing When ever I open it

Put the summary of the bug you're having here

What I expected to happen was...:
I expected the game to open when I clicked the play button.

What actually happened was...:
It popped up with the Mojang screen... the it closed and it said it crashed.

Steps to Reproduce:
1. I opened the game screen where it say's play
2. I clicked play. Then the Mojang page opened.
3. Then it just closed and said crash report.