whenever i try to install said program, i get an error saying

"You must use 'Turn Windows features on or off' in the Control Panel to install or configure Microsoft .NET Framework 3.5 SP1." but when i go there, i don't know how to activate it. what do i look for?
i have Windows 7, and whenever i try to install said program, i get an error saying

"You must use 'Turn Windows features on or off' in the Control Panel to install or configure Microsoft .NET Framework 3.5 SP1."

but when i go there, i don't know how to activate it. what do i look for? and i usually get this answer

http://tinpham.tumblr.com/post/1493418570/help-o