Need more info. 32 bit or 64 bit Java? Mods? Corrupt files? Check the console log using this in a .bat file
java -Xms512m -Xmx1024m -cp "%APPDATA%\.minecraft\bin\*" -Djava.library.path="%APPDATA%\.minecraft\bin\natives" net.minecraft.client.Minecraf t
I'm pretty sure it's 64 bit Java, I don't have any mods and I haven't messed with any files, and when I try to run the .bat file it still shuts down immediatly.Okay I feel stupid now

Minecraft.exe somehow got saved a a .txt file, I don't know how.
Buut anyway I fixed it, thanks for trying to help.