Windows 8.1 Dot.Net 3 Feature Enable using Operating System media offline
If you are having trouble in getting the Dot.Net 3 feature to enable on your Windows 8 machine, there is a way that you can do this offline by using DISM and the original Windows 8 media.
Dism /online /enable-feature /featurename:NetFx3 /All /Source:<drive>:sourcessxs /LimitAccess
Once you are happy you have entered the correct source drive, press enter and it will start to install the feature from the original media.
When it has completed, you should see something similar to this: