Windows 8.1 includes .NET Framework 4.5 development platform, but you’ll need to install 3.5 or 2.0 if an older program requires a specific version.
If you need to run or install an older program on Windows 8.1 you may experience a hiccup or two. That’s because the latest version of Windows requires previous versions of Microsoft’s .NET Framework. The .NET Framework is not enabled by default in 8.1, but it’s easy to install both versions so you can continue rocking your old software programs on the latest OS.
Enable .Net Framework 2.0 and 3.5
From the Start screen type: windows features and select " Turn Windows features on or off."
The Windows Features screen will come up on the desktop. Tick the box next to .NET Framework 3.5 (includes .NET 2.0 and 3.0) and click OK.
Wait while .NET Framework is installed on your system — it only takes a few seconds. Immediately afterward you’ll be prompted to download updates for it.
That’s it! Now you’ll be able to install and run your older programs
