Have an a program that requires .Net 3.5 in order to run on Windows 8.  Frustrated because you downloaded it from the internet and it gives you the error that a newer version is already installed.  No worries, the folks that Microsoft have that worked out for you.

There are two says to enable .Net 3.5 on Windows 8.

Option 1: Manually

• From the state screen do a search for programs (in settings)
• Select Programs and Features
• Click on Turn Windows features on or off
• Select .NET Framework 3.5

• You should be good to install

Option 2: Automatically (probably has given you this popup already if you attempted to install)

• Install an application at requires .NET 3.5
• Click Download and install this feature in the popup

• You should be good