Service Pack 2 with Advanced Security Technologies features a firewall and a popup blocker. It installs the latest windows updates so that Windows XP runs better with less problems. I personally dont use the firewall service, and actually dont use a firewall at all. The pop blocker does a good job, and its built right into the internet options settings in internet explorer. If it blocks a popup, a yellow bar will appear under the address bar. So just in case it blocks a popup that u want to run, you can click on that yellow bar and select for it to temporarily run. Or if a pop isnt blocked, you can go into the internet settings under tools, and have it blocked so the same popup doesnt run again. You can download Service Pack 2 or if anyone wants the CD (free) from Microsoft follow this link: http://forums.xisto.com/no_longer_exists/