How to: Set Environment Variables
The vsvars32.bat file sets the appropriate environment variables to enable command-line builds. For more information about vsvars32.bat, see Knowledge Base article Q248802.
If the current version of Visual Studio is installed on a computer that also has an earlier version of Visual Studio, you should not run vsvars32.bat or vcvars32.bat from different versions in the same Command Prompt window.
To run VSVARS32.BAT
From the Start menu, open the Developer Command Prompt for VS2012.
Change to the Program Files\Microsoft Visual Studio Version\Common7\Tools or Program Files (x86)\Microsoft Visual Studio Version\Common7\Tools subdirectory of your installation.
Run VSVARS32.bat by typing VSVARS32.
VSVARS32.bat can vary from computer to computer. Do not replace a missing or damaged VSVARS32.bat file with a VSVARS32.bat from another computer. Instead, rerun setup to replace the missing file.