Default icons for Windows applications?
For Visual Studio 2012 and 2013:
The icons are not in the program folder any more.
You can download the Visual Studio Image Library which contains most of the icons at http://www.microsoft.com/en-us/download/details.aspx?id=35825
It contains many icons from Visual Studio, Office,...
check out http://www.famfamfam.com/lab/icons/ very nice and exhaustive icon sets. as far as I can tell they are free.