Question about user accts. and admin. with Windows Live Mail

My brother and I are going to be sharing a computer.  I have administration privileges as it is mine.  I want to share common programs, but be able to set him up as a user.  I don't use Windows Live Mail, but he does.  How can I set him up as a user, so he can access Windows Live Mail through his user account and I cannot with the admin?  Since he uses it only himself, I wanted to give him a sense of privacy as well as let him create his own files, etc. that I can't see and him vice versa.  Help?