Windows 8.1: where did the basic (professional) background go?

Hi,

I do like Windows 8.1 but where is the default (professional) background go?
I can't seem to set it correct: all kind of awfull colours that continuously change, nice themes but not for a professional usage.

Please advise: just a plain Windows 7 clean background/them I'd need.
Microsoft, why on earth did you do this, at least if you do want us to use Windows 8 professionaly?

J.

Jan Hoedt