This issue started happening a few days ago. I'm not sure what I did before the problem started but I either updated java or clicked on the force update button in options in the login screen. After that minecraft would load a bit but would then stop toward the end. I have tried updating java, deleting the .minecraft folder, redownloading the client, restarting/shutting down the PC, running as admin, even a combination of these but nothing works.
Yea thats happened to me I think you tried to install something it either means you installed it wrong or its too much for your computer.
Solution- Download minecraft again.
check your antivirus/firewall settings, and assure there's no conflicts(add an exception if there is)
try to connect through the webclient: http://www.minecraft.net/play
Solution- Download minecraft again.