Actually, now both my parents and most of their friends are now using Firefox because I'm fixing their systems. I've found that most of the time when I'm asked to help, it's due to some form of spyware taking advantage of the lax security in IE and installing itself on their system. As part of the clean up, I install Firefox, remove most of the default IE shortcuts, set Firefox as the default browser, and set IE to not ask. Then I explain why they should use Firefox instead. While I'm sure that my words are mostly ignored, most people tend to use the most convienient browser. Since most of these people don't even know how to make a shortcut, much less how to change a browser association, they start using Firefox until it feels natural.