Win2000 password

I have installed win2000 on a number of new computers. The passwords are needing to be reset every 30 days by the users – pain in the rear as an administrator. Not only that but when they reset their password they can no longer login to their computers – even tho they use their new password. I have to go in as administrator, change the password and then it’s ok. They are all setup as power users. What’s going on?

sharon