When I click play (with any version of MC) and it takes me to the Mojang loading screen, it will load for a few seconds and then crash.

When I click play (with any version of MC) and it takes me to the Mojang loading screen, it will load for a few seconds and then crash. I've tried every solution I could think of. The problem started yesterday while I was playing on a server. I'm not sure if I accidentally changed my settings, or if it's a bug.