Network key switcheroo

Dear Geeks,

I'm running xp pro sp3, avast, ccleaner. Recently while attempting to connect to a wifi cafe, the connection hung up on "validating identity." Under "change advanced settings" in "wireless network connections," "wireless network connections properties," "wireless network tab", under "properties" for the selected source. Encryption is WEP. When I entered the ten digit alphanumeric password from the cafe, + confirmation, click ok, to no effect. Immediately hit properties button again, and the network key is reset to eight asterisks. I tried numerous times to get the properties wireless network tab to accept a new key, and it never would. Any ideas? It's not a panic situation by any means. I'm sure every problem in xp has been plumbed at majorgeeks. Or do I need an internet exorcist? Thanks in advance for the help!