Though this may (or may not) pertain to Windows XP w/ service pack 2, here's what Symantec says about having BOTH "Windows XP Firewall" & "Norton Personal Firewall" or "Norton Internet Security" programs running at the SAME time:
http://service1.symantec.com/SUPPORT/sha...=&osv=&osv_lvl=

For now, I'm going to continue to let my 'Norton Personal Firewall' software solely act as my computer's firewall, and wait to read feedback reports from the computer experts, before switching to "Windows Service Pack 2" to handle my computer's firewall tasks. I'll be anxious to hear from the computer experts here about their recommendation regarding 'when' it's actually safe to install 'service pack 2' as well as deciding WHICH firewall & security software to use: Norton's or Microsoft's? - Scott