Click Start, Programs, Administrative Tools, Active Directory Users and Computers.
Expand your Domain. Look in the users container. You shoudl see a listing for Administrators. It will have an icon with two heads. Double click it. Click the tab labeled Members. Select all the ID's you don't want to be members and hit the Remove button.
For your files, right click a folder and choose Properties. Click the Security tab and check what level rights your users have and adjust accordingly. Your users probably just need Read, Write and Modify.
Click the Sharing tab and check out the share permissions. Adjust as needed.
Share permissions and NTFS security permissions combine witht he most restrictive rights taking precedence.
I hope you find this post helpful. Please let me know if it was.
Regards,
Mark