Getting Administrator Profile Back

Went to deploy sofware from a server – Administrator login & password required on each workstation – found that XP Pro had had the Administrator User Profile renamed and/or the Admin User Icon deleted.

Attempts to rename the primary account (which has Admin status) to Administrator and attempt to create new Administrator profile both resulted in “Admin account already exists”. There is an Administrator profile in Documents and settings, removal of which has no effect. Anyone have a clue as to how to correct this? Many thanks in advance!