Problem with .NET Framework 3.5 SP1 Setup?

[lutesolo]

I've searched all around for a solution to this problem and am coming up empty. I bought DD in the Humble Bundle, and when I try to run it on Steam, I get an error stating "You must use 'Turn Windows features on or off' in the Control Panel to install or configure Microsoft .NET Framework 3.5 SP1." I'm on a practically-new computer running Windows 7, and if I'm not mistaken 3.5 SP1 is already installed. I'm at a total loss for what to do.

I've verified my local files, I've uninstalled and reinstalled... nothing seems to work. I've even tried downloading and installing the .NET 3.5 SP1 directly from Microsoft, but got the same message. Has anyone else experienced this, and if so, is there a workaround? I got DD on the cheap, so if I can't play it I guess it's no big deal, but it's nonetheless frustrating.

[Albertafox]

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

To follow what the error said.
-go to programs and features in control pannel.
-on the top left you should see "turn windows features on or off". Go there.
-Should see a list, check to make sure "microsoft .net framework 3.5.1" is checked.
-The two sub-headings under that do not have to be checked.(at lest for me)

If it is already enabled(tik) then remove it, reboot, re-enable it, reboot and see if its working.

[lutesolo]

Many thanks! It's so obvious, but somehow I was sure that this was something I couldn't fix just by rooting around in the Control Panel area. Thanks again!