https://www.dotnetzone.gr:443/cs/blogs/birbilis/archive/2014/12/12/howto-install-net-3-5-component-in-windows-8-1.aspxI just installed .NET 3.5 on a Windows Enterprise 8.1 system that was failing to bring the needed files from the network To do this I opened a command prompt with elevated rights and ran a single command, having the Windows DVD at drive F: Dism /onlineelCommunityServer 2.1 SP3 (Build: 20423.1)