How do I install .NET Framework 3.5 on Windows 7?

I need to install version 3.5 of the .NET Framework in Windows 7, but when I try to install it, it shows the following error:

"Turn on/off .NET Framework" option in System Features

I tried doing this, but I don't understand what it means. Can anyone help me?

Solution 1:

That message is trying to tell you that you need to install .NET 3.5 a different way under Windows 7. Because it's included as part of the operating system, you use the "Turn Windows features on or off" function to get to it, instead of installing a downloaded redistributable package.

1. Open the Start menu and click "Control Panel".
2. Under the "Programs" category, click the "Turn Windows features on or off" link text.

Solution 2:

Run the following command as an admin:

DISM /Online /Enable-Feature /FeatureName:NetFx3 /NoRestart

That'll install .NET Framework 3.5 SP1, 3.0 SP1, & 2.0 SP1 ... same as enabling it through the GUI in Control Panel.

Solution 3:

You may disable/re-enable the Microsoft .NET Framework 3.5.1 within the Control Panel to effectively repair it:

Control Panel > Programs and Features > Turn Windows feature on or off.

Uncheck the Microsoft .NET Framework 3.5.1 entry. Click OK to accept this setting and return to Turn Windows Features on or off to re-enable Microsoft .NET Framework 3.5.1 by checking the box.