1.7.2 wont work on my Minecraft

If im on 1.7.2, i cannot log into any servers. when i do, it just crashes right away, and I've tried every thing to fix it. i don't know if its just my computer or just the update.

At lest try to fix the 1.7.2 or tell me if i need to update some thing....

Every time i log in, it crashes. And some other people that i know have the same problem .

Steps to Reproduce:
1. Look at the update
2. Just see if there is problems with it
3. Tell me what happened