Scenario: You get the following error on windows 8 while trying to add DotNet 3.5;
If you downloaded Windows 8 from Microsoft run the following line
Dism /online /enable-feature /featurename:NetFx3 /All /Source:C:ESDWindowssourcessxs /LimitAccess
If you used a DVD to install windows 8 do the following;
Dism /online /enable-feature /featurename:NetFx3 /All /Source:D:sourcessxs /LimitAccess
This assumes your DvD is Drive D:
You will also need to uninstall the following windows updates.