The Problem:
During installation the following error message is displayed:
ASCOM Platform 5.0b
This setup requires the .NET Framework version 2.0.50727. Please install the .NET Framework and run this setup again. The .NET Framework can be obtained from the web. Would you like to do this now?
The Solution:
1. Go to Control Panel ---> Windows Updates ---> install all essential/important updates.
2. A new build of win 8.1 will include .NET Framework 4.5 but no earlier versions. Download and install .NET Framework 3.5, which includes earlier versions 3.0 and 2. Once installed, You have to go to “turn windows features on/off” to put a tick against .Net 3.5. Then the install can go ahead.
http://www.microsoft.com/en-ca/download/details.aspx?id=21