It solved my problem for the lastest versions of minecraft...
But what if I want to play with mods in older versions which doesn't have an .exe launcher?
I have the lastest version of java for windows 8 and tried right clic the jar file then "open with" and select java.
Also tried the jarfix and doesn't work.
I downloaded some forge versions to be sure it's not a bug or something but nothing works.
Help please