Binding Mac BookPro to AD

I am going for Mac certification.  I have an MSCA from MS.  

I am trying to bind my MacBook Pro to AD.  I can do it, but when I try to log into the MBP with the windows authentication it only accepts the Administrator of the Domain credentials not the user creds.  When I log into the administrator credentials, I can get in and browse shares without authenticating.  I really need help in figuring out why I can not use the regular user.

Thanks,

Rick