I have several versions of .NET in C: \ WINDOWS \ Microsoft.NET \ Framework \
Which system variable controls what runs by default?
There is no "System" variable for this.
Your application (.Net assembly) is compiled for a specific structure and this structure is then used to execute it.
These are separate applications that determine which version of the .NET platform it will run on.
If you are talking about ASP.NET applications, the version on which it will run is installed in IIS.
The application itself has a manifest that tells your system which version of the framework it targets.
Your application will determine which ones