One of the machines I run is with WinXP 64bit and the last service pack for that version which is SP2.

I have never had a virus or worm on this or any other Windows machine I setup at home for 17 years and counting, and I don't run AV software.

I simply disabled everything I didn't need - most notably the Server service.

Obviously I don't store anything critical on this machine alone.

Some more info here;

"Server service
You can disable the server service unless you are sharing files on your hard drive or your printer. If you have a DSL or cable modem, stop this service. Hackers will get nowhere if you do."

[link to m.windowsnetworking.com]

There are a few articles around the web about disabling unneccessary items, but very few of them mention this service which is funny because it is the biggest single win of them all from a security perspective.

[link to www.marksanborn.net (secure)]