I too have been running WinXP or a few years. Have had to re-install a few
times
but that's mostly because I do lots of development work, install and
uninstall all
types of software. I find a reinstall every 6 to 12 months to be a nice way
to clean
up the system. It's a bit of a pain but OK by me.

I like WinXP. Serice pack 2 certainly seems quite secure with it's firewall.
I used
to use zonealarm.

Computer Associates is giving a 12 month (12 month!) free trial of their
anti-virus & firewall software, so that's what I'm using there.

And a helpful site for WIndows fixes, etc.
www.Annoyances.org

Peace Out,
Gary