I had this problem, also where my mom was a limited user, but I wanted her to play games. I added her account to the power users, and this alowed her access to more games but not all. I eventualy gave in and gave her an admin acount.

However if you would like to try the power user, go into admin tools> computer management from the controll pannel. Double click on Local users and groups, and then users. Double click the user you would like to make power user, and click on the Member of tab. Click on Add, then Click Advanced, and Find now, in the list chose power users, and click ok.

This works in XP Pro I dont know about home