windows XPsp3 dosen’t cache domain username/password

Its a little wired. i am configuring a new laptop for a user, everything is fine , except it doesn’t remember the domain user name and password when user try to log in to the laptop without plugging network cable. so every time anyone needs to log in to this laptop , it needs a network cable. I was wondering if anyone has any suggestion what to do ?? thanks

PS: everything is working on this laptop fine. It is running WINXP sp3.