Ok... first get a fresh minecraft so back up all your important files like screenshots, saves, servers.dat..etc. Once you have a fresh minecraft go into the .minecraft folder and open bin. In the bin folder you will need to open minecraft.jar with winrar (windows) or the unarchiver (Mac). Once you do that you will get a folder titled minecraft. Delete the minecraft.jar and rename the minecraft folder to minecraft.jar. Now, open your minecraft.jar folder and look for META-INF or META.INF and delete it. Now open the minecraft forge (universal) folder and copy and paste all of the files from the minecraft forge folder to the minecraft.jar folder. Once you have done this just start up minecraft and everything should work fine.
