The pay for ver. of PestPatrol has the updates and can deal with upcoming threats, the free stuff simply can't do the job, you can't keep it current, unless you download it once a week or so. I finally bit the bullet and paid for it, even so, it won't catch everything due to the fact that the threats are ever changing and definition updates are the only way to stay current, and they know that, thus the free and pay version. The crack dealers do the same thing, it's just a different comodity. If you're wise in the ways of windows registry, you can identify the pests with PP free ver. then manually remove (with the help of their web site) the offenders yourself. XP sp2 has all the updates (patches and security plugs) rolled into one package, plus some other good stuff, this sp is a good one and is a must have. The sp2 offers a decent firewall, it allows you to control access like Black Ice does, and that's the rub, shut um out b4 they get a chance to do any damage. Updating weekly is the norm anymore, and one almost must have 1) firewall. 2)Anti-virus. 3) Anti-spyware. 4) Anti- adware. 5) Windows critical updates, constant changing threats. I also must say, don't spend a lot of time on removing deep or numerous pests, back up your data and do what my father-in-law taught me, B.T.D. (bare the drive) format re-install windeers.