Windows updates, what updates?
Seriously, this all is just a giant FUD operation towards the computer challenged people.
For the same reason I don't use an anti-virus, because the only thing they do is to slow down your computer (the same thing that some viruses do).
I sometimes check a suspicious file with a web-based anti-virus, and every six months or so check the whole computer, but so far I've NEVER been infected (since I'm the only one using this computer, that means in three years).
But that's also maybe because I don't use IE, and have a NAT router that blocks everything I tell it not to...