Administrator icon

When I first installed WinXP Pro the only user was Administrator (at the welco;e screen). I used it quite a lot, then one day I installed another user with administrator rights.
From that moment on. the welcome screen shows only the new user icon, no longer the Administrator’s. hence I can no longer log in on the Administrator account (which contains quite a few of the applications the new user has not like the emails received on the Administrator account}
Could you help me by telling me how to have the Administrator icon back to the welcome screen, please?
Thank you