About Login Script

Hi,
I would like to write one script and i need help in it.I am using windows 2000 adv. server with active dir. installed and i want the password of administrator will automatically change in 7 days.I don’t want to change it manually can it be possible if yes then i would like to know how.

I will be thankful to if someone give me guidance on it.
Regards.
Anurag.