type
 PTOKEN_GROUPS = TOKEN_GROUPS^;
function RunningAsAdministrator(): Boolean;
var
 SystemSidAuthority: SID_IDENTIFIER_AUTHORITY = SECURITY_NT_AUTHORITY;
 psidAdmin: PSID;
 ptg: PTOKEN_GROUPS = nil;
 htkThread: Integer; { HANDLE }
 cbTokenGroups: Longint; { DWORD }
 iGroup: Longint; { DWORD }
 bAdmin: Boolean;
begin
 Result := false;
 if not OpenThreadToken(GetCurrentThread(), // get security token
  TOKEN_QUERY, FALSE, htkThread) then
  if GetLastError() = ERROR_NO_TOKEN then
  begin
  if not OpenProcessToken(GetCurrentProcess(),
  TOKEN_QUERY, htkThread) then
  Exit;
  end
  else
  Exit;
 if GetTokenInformation(htkThread, // get #of groups
  TokenGroups, nil, 0, cbTokenGroups) then
  Exit;
 if GetLastError() <> ERROR_INSUFFICIENT_BUFFER then
  Exit;
 ptg := PTOKEN_GROUPS(getmem(cbTokenGroups));
 if not Assigned(ptg) then
  Exit;
 if not GetTokenInformation(htkThread, // get groups
  TokenGroups, ptg, cbTokenGroups, cbTokenGroups) then
  Exit;
 if not AllocateAndInitializeSid(SystemSidAuthority,
  2, SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS,
  0, 0, 0, 0, 0, 0, psidAdmin) then
  Exit;
 iGroup := 0;
 while iGroup < ptg^.GroupCount do // check administrator group
 begin
  if EqualSid(ptg^.Groups[iGroup].Sid, psidAdmin) then
  begin
  Result := TRUE;
  break;
  end;
  Inc(iGroup);
 end;
 FreeSid(psidAdmin);
end;