My minecraft will not let m go on any servers on 1.7.9 or 1.7.10 every time it sends me to a crash report

Put the summary of the bug you're having here

What I expected to happen was...:
I could get on the server and it would be fine

What actually happened was...:
It crashed my minecraft and wont let me on anything tht requires 1.7.9 or 1.7.10
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...