WEP problems!

I have a D600 with Win XP Pro (all the latest updates) and the Dell 1300 WLAN wireless card (mini) with the latest drivers from 11/2003...

The access point we use (Dell AP-1000) is configured to allow WEP and non-WEP connections.

I connect fine without WEP. If I am connected without WEP, I can open the properties and add the WEP key (we use 128-bit encryption, so the key is 26 hexidecimal characters). When I click OK and save the changes, the connection changes to a WEP connection and works fine.... UNTIL the next time it needs to connect. If I disconnect or close the connection manually by disabling it, or reboot or whatever, then when it tries to reconnect it will say "Connection failed!" and not connect until I remove the WEP. Also, when I go into the properties, there are a lot fewer than 26 characters in the text boxes!!!

What is going on and how can I resolve this?