when i download mc to pcand log in it keeps crashing

Put the summary of the bug you're having here

*What I expected to happen was downloading and playing mc
Describe what you thought should happen here

*What actually happened was mc keeps crashing when i log in
Describe what happened here

Steps to Reproduce:
1. there is a problem
2. i just downloaded mc to pc from mc site
3. it just crashed when i logged in (keeps crashing)