[megalottachoc]

Most of it comes from a philosophical perspective, rather than a technical one. In many forms, viruses usually find their way in from software vulnerabilities, leaving deliberately (albeit unknowingly) installing in the minority. With the open source/free software development cycle, it should be possible to eliminate most avenues of vulnerability.

So in short, the questions we should be asking are:

1. How do viruses find their ways in?

2. And, what can be done (as a user or developer) to prevent that?

These are obvious, I know, and the software devs for Windows aren't deliberately writing insecure software, but these questions are ones better seen from a behavioural point of view.