procedure OpenMailClient; const cMailClient = '\SOFTWARE\Clients\Mail\'; var reg: TRegistry;
RegClientDefault: string; begin reg := TRegistry.Create; try
with reg do
begin CloseKey;
RootKey := HKEY_LOCAL_MACHINE; if OpenKeyReadOnly(cMailClient) then RegClientDefault := reg.ReadString(''); if OpenKeyReadOnly(cMailClient + RegClientDefault + '\shell\open\command') then WinExec(PChar(ReadString('')), SW_SHOWNORMAL); end; finally reg.Free; end; end;
procedure TForm1.Button1Click(Sender: TObject); begin OpenMailClient; end;