dot net framework 3.5 (includes 2.0 and 3.0) is very important to installing many softwares.Many software works on dotnet only.In windows 8 or 8.1 or 10 has some methods found to install .net framework3.5 .In online method doesn’t need windows installation DVD.It download Directly from microsoft.In offline need windows installation DVD to install .net framework 3.5.In windows 8/8.1 or 10 has default tool named as Deployment Image Servicing Tool.
Offline Method to Install .net framework3.5
1.Insert windows 8/8.1 or 10 DVD
2.Open Command Prompt as administrator
3.Eg: G: is a windows DVD Path
4.Enter the Following Command
Dism /online /enable-feature /featurename:NETFX3 /ALL /Source:G:sourcessxs /LimitAccess
5.Wait Until Process Finished
6.Finish
Online Method
1.Open control panel
2.Click Program and features
3.Click turn Windows feature on or off
4.Tick .Net framework 3.5
5.Wait to Install
6.Click ok
Using Auto Script Method
Tutorials to Install offline
Your post captures the issue peecyftlr!