HOW TO - Install .NET Framework 3.5 on Server 2012 R2

1. To install Report Viewer 2008 needed to run WSUS reports, you need .NET Framework 2.0.
2. .NET Framework 2.0 is part of .NET Framework 3.5
3. When you try to add this role/feature, you’re told "source files could not be found".
4. Locate the 2012 R2 ISO and copy it locally.
5. Right click on the ISO - Click Mount
6. Assuming it mounted as F Drive run this command from an elevated CMD (see below)

Dism /online /enable-feature /featurename:NetFx3 /All /Sourc

e:F:\sources\sxs /LimitAccess

7. Then attempt to install the ReportViewer.exe again and it should work.