As a parent of a teenager, I find that I sometimes have to resort to drastic measures like withholding WiFi access until chores are done.
Sometimes, I will change the WiFi password and leave a note in the Teen's computer saying "The WiFi password has changed - do your chores and then I'll tell you what it is"
The problem is that Windows 7 then doesn't handle this at all gracefully. Why can't it just pop up a message if it encounters a WPA failure on a network it was previously authenticated to, simply requesting the new password?
At the moment, it is necessary to drop the connection to the network, go to "Manage wireless networks" and "Forget" the network, then go back to the tray and re-add the network.
This seems to be beyond The Teenager, and as a result usually ends up in a tech support call to restore connectivity.
Be really nice if Windows handled this event more gracefully!