PEAP doesn't request credentials

I have a WPA network which uses PEAP to authenticate users. A while back,
the server certificate expired. Rather than go through the trouble of
re-installing the new server certificate on every wireless node, I went
through and changed the settings to not validate the server certificate.
This restored functionality to most of the nodes and isn't the problem, just
setup.

After the server certificate failed, but before the node was reconfigured,
it was unable to connect to the access point and therefore flushed the cached
PEAP credentials. Therefore, on most of the nodes, after the configuration
change was made, the user gets prompted for PEAP credentials and the node
reconnects as soon as these are given, no problem.

HOWEVER, I have three nodes, all of which use Airlink101 wireless adapters,
but each a different model, for whom the post-reconfiguration behavior was
different. On these stations, Windows XP immediately fails the connection
and never requests PEAP credentials. If I remove the preferred network and
re-create it, Windows never asks for credentials but instead immediately
fails the connection. I checked the registry settings for cached PEAP
credentials, and there isn't anything there.

I know there is one obvious path-- replace the Airlink101 WNICs with a
different brand, but does anyone have any other suggestions that only require
spending time, not money?