Steven047 :
I get an error message while trying to install office 2007 on my windows 8.1 Pc, the error message is " There are no products affected by this package installed on this system"
That error message points to you trying to install a Service pack for Office 2007, not the actual Office 2007.
Since you don't have Office 2007 installed, it fails.
What precisely are you trying to install, and where did it come from?