Originally Posted by the relevant part

As it turns out, if you use the Microsoft Windows XP SP 1-based Wireless Zero Configuration service (my note: I imagine that Vista runs some updated variation/version of this service, right?)to manage your wireless (aka, the "built-in client"), you're probably running into a horrible bug that Microsoft calls "behavior by design." The gist of this is as follows: if your wireless network is set to not broadcast your SSID, Microsoft's wireless manager will periodically drop your non-broadcasting WiFi connection in response to the presence of a broadcasting SSID-based network. You won't fully associate with that network, but the service will pop-up and tell you that there are multiple wireless networks to join, even if you have removed all other networks from your preferred settings (this contradicts Microsoft's report, which says it only affects preferred networks). The upshot of this is that you, the user who changes his default SSID and then sets it to not broadcast (as most security guides, and most hardware setup guides will tell you to do), now gets dropped off your network when you neighbor shows up with his new D-Link wireless router and not only fails to change the SSID from default to something else, but does not turn off broadcasting, either. While many may debate the security benefits of disabling SSID broadcast, it is a practice that is recommended by most manufacturers of wireless products