I am still using Windows XP. Someone recently told me that while Windows 7 has a built-in firewall that is good enough on its own, the XP version is not. Therefore, I was advised to continue using third-party firewall software. However, I note that ZoneAlarm slows my computer somewhat. I had also tried Comodo, but didn't much like it. (I stopped using Norton and then McAfee years ago, because they conflicted with my order entry software at that time, causing unacceptable delays.) And so my question is this: is the XP built-in firewall indeed insufficient so that I really should continue to use a third party firewall? I would appreciate any comments and insights you may have. And yes, I use anti-virus software.