Auto Install Feature for .PHP File

We have an client based application built in Visual C# 2010. Periodically this .exe file automatically accesses a php file we have on our server. We want to provide our users with an auto install feature. It should automatically install a new .exe (software product) on our end user's machine. Completely silently and automatically. T We need php code added to our existing php file to install a new .exe. Including error checking, accounting for UAC limitation, .etc. Anything that might prevent an auto silent install or cause our php file or .exe to "bomb". So, very basic php coding. Here is an example of what I'm looking for: