Step by step solution

Start a VisualStudio command prompt

Start a VisualStudio command prompt and navigate it to the place where devenv.exe is located. On my System this is C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE

Create a manifes file from devenv.exe

Execute the following command:

mt -inputresource:"devenv.exe" -out:devenv.exe.manifest

This will create the file devenv.exe.manifest

Edit the content of devenv.exe.manifest

Change the level value of requestedExecutionLevel from asInvoker to requireAdministrator

Write the manifest back into the devenv.exe

Execute the following command in the visual studio command prompt:

mt -outputresource:devenv.exe -manifest devenv.exe.manifest

Check whether visual studio 2012 starts as administrator

Just double click any .sln or .proj file, and check whether visual studio starts as administrator or not.