minecraft would not load

Put the summary of the bug you're having here

What I expected to happen was...minecraft would auto down load:
Describe what you thought should happen here minecraft should download

What actually happened was...:there was an error and it didnt
Describe what happened here it stopped working

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...download
thats it

3. ...