My sister-in-law dropped off her daughter's tower machine for a rebuild. The first thing they asked for is for me to wipe the drive and to install Linux on the machine. They don't even want a dual-boot machine, but, pure Linux! It seems that they are tired of the viruses/trojans on windows and the A/V software is really slowing down their machine. I know Linux isn't perfect, but, is a lot more secure by default and I will be turning on all of the various options to harden the machine as much as possible. I also will build normal user accounts that cannot add/change/delete programs from the system and then show them how to use the special account with root priviliges for when they have to update the system.
I will be re-imaging the machine to PCLINUX and installing Libre Office, Games and educational packages for her as they wanted a fully loaded machine to do office work, games and allow the kids to 'play' with some of the free educational packages that comes with the distro.