We just got WindowsXP with

Question

We just got WindowsXP with Vista and it came with 2 accounts -- both of them set as the Administrator. Of course, I changed one of the accounts to "limited", set the other as the administrator and gave each passwords. Problem? I can access them both but the Administrative one will not allow me to make any changes. (I can not even access "system restore.") What I need to do? I need to change the limited one to Administrative but cannot do so in the Administrative? Can anyone help me?