Installing .NET framework 3.5 is extremely easy using Deployment Image Service and Management (DISM).
You need a copy of your installation media.
- Insert the installation media.
- Open CMD.
- Just type the following code in a CMD window.
- Change the installationMediaDrive to the drive letter of your installation media (D, E, F, etc.)
- What a few minutes while the feature is enabled.
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:installationMediaDrive:\sources\sxs