Why does windows insist that the wireless network is 'new' after the router reboots?

[dtbullock]

Every time I reboot my Cisco IOS 800-series router, all the Windows 7 machines 'identify' the wireless network as being a 'new' network, forcing users to classify it as Home/Work/Public all over again (and more painfully, causing host firewalls to think this 'new' network is untrusted).

What have I failed to do?  I'm thinking perhaps I've failed to save some kind of key persistently, but can't work out which one.

[dtbullock]

So far I have found http://blogs.technet.com/b/networking/archive/2010/09/08/network-location-awareness-nla-and-how-it-relates-to-windows-firewall-profiles.aspx and this has clarified the question a little: it seems that Network Location Awareness (NLA) identifies the network differently and wants to assign a new (NLA) 'profile'.