If you are trying to install the forge modding package, but the command prompt comes up as
THIS APPLICATION FAILED TO START BECAUSE ITS SIDE BY SIDE CONFIGURATION IS INCORRECT. SEE APPLICATION LOG FOR DETAILS.
This is because forge doesn't have the correct C++ files to run on your system. To work around this, get python 2.7.3, or higher if you wish to write in python yourself, from here: http://www.python.org/getit/.
Then let it install and then run install.py in the forge folder. As well in the FML folder.
Reply if this helped, or you still need help