My machine has been very stable with no popups or other problems for a long time now. I am using WinXP Pro sp2, the beta of Windows firewall, Norton AntiVirus and Firewall, and a Linksys router. Every once in a while, I will run adAware.
Also, before I install ANYTHING, I let Norton take a look at it. I NEVER open any email attachments that could contain an executable script of any kind (even from close friends). Windows now warns me whenever a web site wants to install an Activex file or such, and there has to be a really good reason for me to allow that to happen.
I do not use a spam blocker. Even so, spam is not much of a problem. I only get from 1-10 per day - not bad. I think I know where the leak is coming from, and I am going to take steps to plug that.
Any time I receive a phishing email, I report it to the target business so they can get on the criminals quickly; just doing my little part to fight back.
Chuck