Well do you have any ideas on what the problem might be? Is it common?
Also, it's not like it says how to install it on here anyway. Did I do it right?
Archiving tool: 7-zip
1: Open minecraft.jar and minecraftforge-client-3.3.7.135.zip
2: Select everything in minecraftforge-client-3.3.7.135.zip and copy it over to minecraft.jar
3: Delete META-INF
EDIT: Okay stupid me. There is a readme file at the bottom of the zip file. But the installation instructions were the same as what I did! What's wrong?