Windows XP reinstalls and viruses

I thought I would post this here hoping that someone would read this and take my advice and perhaps incorporate a portion of this post into one of the existing stickys. I just spent the last 2 hours helping my brother recover from a worm he received by simply connecting to the internet. He's an extremely conscientous user - firewall, anti virus, anti spyware, all updated - learned it all from me lol. The problem is that he just reformatted his hard drive and connected to the internet with an unpatched windows xp sp1 to download windows updates. It is essential that no computer should be connected to the internet with an unpatched version of sp1 or any previous version of windows without installing a firewall prior to doing so. Minutes after he connected, a worm infected his system while he was downloading windows updates. I had the exact same thing happen to me while reformatting. People should keep a copy of a free firewall like Zone Alarm on a disk so that if you reformat, you can install a firewall prior to attempting to connect to the internet. If you have broadband (cable, dsl) don't even think about plugging the ethernet cable into your pc until you have installed a firewall. It's dangerous out there!