Say I have .NET Framework 2.0, 3.0, 3.5 installed for an Asp.NET web application.
I realize that Framework 3.0 and 3.5 are just extensions to Framework 2, what is less clear is how 3.0 and 3.5 interrelate.
Am I safe uninstalling Framework 3 if the Asp.NET application targets 3.5?
Those three versions share the same CLR version (2.0) and each new version just adds new features not available in the previous version. This basically means 3.0 depends on 2.0 and 3.5 depends on 3.0 and 2.0 so uninstalling 3.0 is not possible unless you also uninstall 3.5.
For detailed information about .NET Framework version you can check out:
.NET Framework Versions and Dependencies