PEAP Authentication trouble

I work in a hospital with a wireless network. It is a non-broadcasted SSID
that uses PEAP authentication. We have a mandatory policy for passwords that
require them to be changed every 60 days.

We use Microsoft for PEAP authentication on our XP machines. Whenever
someone changes their domain password, I have to completely blow out the
wireless connection on their machine and recreate it or it won't keep signal
for more than one second, since it caches the login the first time you type
it in. We've done a bit of snooping around and Microsoft claims there is a
registry key you can reset to force it to ask for the user/pass again, but it
doesn't seem to work.

Anybody got any ideas on how to flush out that cached password without me
having to recreate the connection?

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