If it will be good than simple "Windows 7 - back to normal" phrase can be good.
I can imagine a spot with guy in suit (and super BMW and lot of gel on hairs - white and shiny all of it) vs. particular John Smith being (in American car, obviously - if there's any). The fop can throw money away everywhere: easy girls, easy life and ignorance. While "normal" guy is presented with family, kids and happy dinner table. Maybe daughter coming from school and... delicate text (mentioned above) of advertisement.
Or maybe just a "Windows 7 - no more lies"