1, the installation package download NET Framework 3.5
http://download.windowsupdate.com/d/msdownload/update/software/updt/2015/11/microsoft-windows-netfx3-ondemand-package_421a25bf409692045d1cbfab0d99f8def8d95d3f.cab
2. Copy the downloaded files to be copied to the Windows folder on the C drive
3, cmd start as an administrator
4, first enter dism / online / cleanup-image / restorehealth
5, then enter dism / online / enable-feature / featurename: NetFX3 / All / Source: D: \ sources \ sxs / LimitAccess
Screenshot:
7, open the Control Panel \ Programs \ Programs and Features
Click the button to activate or deactivate the function windows
Click OK OK