I ran into a simular situation not long ago with an other program. Window net frame work is a native widows feature. To install or uninstall it goto programs and features then to add or remove windows features. If it is not checked there, check it(the box) to turn it on. If it is checked then uncheck it reboot then recheck it to reinstall it.
Hope this helps.
If it was native it's not now because I ran MS. Framework-Cleanup.
I don't know what you mean by "... goto programs and features ..." but I went to
and that version installed. All now works well.
Thanks for the nudge.