The third in what I’m sure will be a long series of articles on the problems and misery of Vista. I’ve noticed that after certain updates, the Windows Firewall settings are reset. So, if you notice that certain network programs aren’t working, or you can’t log in via Remote Desktop, you may have had your firewall reset by an update.
As far as I know, there is no solution to this. Resetting the firewall is apparently a necessary part of updating certain system components. Of course, if Microsoft cared about the convenience of its users, I’m sure there’s something they could do about this. I think linux manages to update security components without resetting their configuration.
My recommendation is to just turn it off and get a hardware firewall. Securing Windows by trusting the firewall made by Microsoft is like paying your dog to guard your cheese fort.