There is a very easy way to run .NET 3.5 applications under .NET 4.5 (and 4.0), without having .NET 3.5 installed…
Edit the application’s app.exe.config file:
C:\WampDeveloper\WampDeveloper.exe.config
And within the “<configuration>” section, add in:
<startup>
<supportedRuntime version="v2.0.50727"/>
<supportedRuntime version="v4.0"/>
</startup>The above configuration will have the system use .NET 3.5 if it finds it, otherwise it will use .NET 4 (either 4.0 or 4.5).
Whether this work depends on whether the code used in the application is compatible with the changes that were made in the newer releases of .NET runtime. Most applications will be 100% compatible.
Related Information
1. Graph of the default .NET version that shipped with the Windows OS version:
2. Microsoft documentation on the above configuration changes: How to Configure an App to Support .NET Framework 4 or 4.5
3. Microsoft documentation on which versions of .NET that can be installed per Windows OS version: .NET Framework Versions and Dependencies