Why am I not able to apply the update KB3033929 on my Windows 7 computer?

As it says, it's not applicable to your operating system. You either have the wrong version for your OS (bit level/architecture), are missing prerequisites, already have it installed, or you have an update installed that replaced/superseded that update (making this one no longer applicable).

In your case I believe you're missing a prerequisite, Service Pack 1.

According to the KB itself:

Applies to:

Windows Server 2008 R2 Service Pack 1, Windows 7 Service Pack 1

According to the System info image you posted, you don't have Service Pack 1 installed. If you did, it would be noted on that screen:

So you'll need to install Service Pack 1 before that update can be applied.