What happens when user click .NET assembly (EXE)?

When you double click on a .net .exe assembly

Windows' PE (Portable Executable) loader kicks in

If you're on a Windows >= Windows XP it will detect that the executable is a managed executable and will forward it to .net by calling _CoreExeMain in mscoree.dll (_CoreDllMain if you double clicked on a managed .dll). It can use the assembly configuration file to know which runtime to use.

If you're on Windows < Windows XP, the .exe file contains a small native piece of code that will jump to mscoree.dll's _CoreExeMain or _CoreDllMain.

Then mscoree.dll initializes the .net runtime, depending on the global configuration, the assembly configuration file, and what not.

Then if it's a .exe, it will JIT compile its entry point method, and start executing it.

Reference :
http://stackoverflow.com/questions/2788270/what-happens-when-user-click-net-assembly-exe

http://maneshjoseph.blogspot.com/2010/10/what-happens-when-you-click-on-net-exe.html