Font installation weirdness

[karden11]

I recently installed a free downloadable font into my Font Book on my MacBook White, and ever since my fonts in Mail, online on three different browsers (as in whole wikipedia articles), and in my iTunes search box have changed to that font. It's not a particularly hard font to read (it's called Neutraface), but it's also not really a font I want to see anywhere. I've gone into the system preferences on both my regular system and through TinkerTool, but I can't find a way to change the font back to the default. I've also tried disabling and uninstalling the font from Font Book and restarting my computer, but that hasn't worked either. If anyone knows what might have caused this and how to fix it, please let me know. Thanks!