I installed a mod-pack, and when its done installing I press play. The launcher disappears and then a couple seconds go by. Boom! Launcher shows back up, and the game doesn't load up. I've had this issue before, but kept giving up after trying to fix it. I have the latest Java, and I have it set to 2GB of ram. Any help is appreciated, please and thank you!
I didn't find a crash log file, but I found the log file. I don't know if that still helps. Here it is!
Update: I found the crash log, here is one: Crash Log!