Minecraft (.jar) crashed for no known reason

I expected for the minecraft.jar launcher to open Minecraft and launch the game.

When I tried to launch Minecraft from the minecraft.jar launcher, it gave me a crash error report. I tried using the .exe version, with no luck.

1. Open minecraft.jar or Minecraft.exe
2. When logged in and everything, click PLAY
3. Game is supposed to load and be able to be played. Mine would stop loading and give me a crash error report instead.