In trying to make Windows users understand that they can finally be free of proprietary operating systems, the Linux user must be careful not to come off as too-elitist or snooty. We know that Linux is less complex, less targeted for malware, easier to fix/repair/upgrade, and far easier to customize, but they do not.
Linux users must be patient and willing to demonstrate what caused their minds to change, to even consider that their PCs could be run by a non-Windows operating system. Those still under the mindset of Redmond think that Windows is the only system that can run on their PCs -- they have no choices. It is our job to show them the true reality.
Begin by showing your Linux-powered laptop or your very neatly "dual-bootable" desktop that allows the choice of Linux or Windows depending on what needs to be accomplished. While in Linux show them the ease of upgrading, the reduction of the AV nightmares, and the significant inventory of community-supported applications and solutions.
Simply "showing-off" Linux will not do it, but showing them Linux solutions and simplicity will. Be patient with them; they still think the computing world is flat and that sailing into the Linux sea will result in being devoured by sea monsters, or worse, falling off the edge of the world. I know this sounds so much like medieval bunk, but its really the way they have been taught to think about their computing world.
Be patient, be kind, and be persistent. Good luck,