But if you do need another reason to not allow users to be Administrators on their PC’s here is another study that shows a vast majority of the security flaws for Windows or Office have no effect if the user isn’t an Administrator on their PC.

http://lifehacker.com/5506323/remove-admin-access-to-halt-most-windows-security-flaws?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+lifehacker%2Ffull+%28Lifehacker%29