Spybot installed under admin but cann't use fully in user

I installed spybot while logged on as Admin in winxp, and set up an account for my wife as a user. I've read that it's best to use the computer as a user then to use it logged on as admin. I noticed that spybot cann't be fully used when my wife logs on. I tried to activate the immunized function of spybot but get the message that I don't admin rights to use this program. Does that mean that programs that were installed in admin (needed admin rights inorder to install programs) don't fully function when a user is logged on? I wondering how the programs I installed to protect the computer are suppose to work when family members are logged on as users.