LookupAccountName

function LookupAccountName(

  lpSystemName: LPCTSTR;

  lpAccountName: LPCTSTR;

  Sid: PSid;

  var cbSid: DWORD;

  ReferencedDomainName: LPTSTR;

  var cchReferencedDomainName: DWORD;

  var peUse: SID_NAME_USE

):BOOL;