I am the system administrator and am logged in as such. However when I try and make changes, particularly right now I am trying to remove ad yeild manager, my PC tells me these settings are managed by the system administrator and I do not have permission to make the changes. Can you help me either reset the system adminisrator or diable it? This is the only computer in our office. There is no network. Thank you.

look at the administrators group and verify your account is a member.