Havaro

You downloaded the universal version. The forge folder is in the Source version of forge. You can find it next to the universal verison. Put the Forge folder that you downloaded in mcp (next to jars, etc.). In this forge folder you will find the install script.

Read this: http://www.minecraftforge.net/forum/index.php/topic,20.0.html And this: http://www.minecraftforge.net/wiki/Installation/Client You should have done that before you posted.

SRC stands for "source" this is for modders. Players and server owners use "universal": for the whole universe of players and servers.

Forge is not incompatible with nearby all your mods, all your mods are incompatible with forge. Without forge almost all mods would conflict. Search and you will find. http://www.minecraftforge.net/wiki/Installation/Client That's why forge is created. To make more mods compatible with eachother!

Please post an error report, saying that it freezes is most of the time not enough info to help you. Check your .minecraft folder for any .log files. Thanks for trying though. Your problem is probably caused by an outdated version of forge. Use forge 4.X for minecraft 1.3.1 and up from http://jenkins.minecraftforge.net:7070/job/forge/

There is no client version of forge for minecraft 1.3.1 yet. Please use the search next time and read the sticky's: http://www.minecraftforge.net/forum/index.php/topic,1200.0.html

Did you use the "install.ph" in the forge folder? Also, check the wiki page.