Make it open source
Make all Windows operating systems open source, then Microsoft can't ram these new operating systems down our throats.
My notebook came pre-installed with Vista Home Premium, and I can't any older OS to install, even after doing a government wipe of the hard drive.
Microsoft is now in the business of selling protections for it's OS. Let them compete in that area, and let every at the source code, so that we can get a real OS.