procedure RegWrite;
var
  reg: TRegistry;
  Bin: array[0..10] of Byte;
  I: Integer;
begin
  for i:= 0 to High(Bin) do Bin[i]:= i;

  reg:= TRegistry.Create(KEY_ALL_ACCESS);
  with Reg do
  try
    RootKey:= HKEY_CURRENT_USER;
    OpenKey('Software\my_sub_key', True);
    WriteInteger('Integer', I);
    WriteDate('Date', Now);
    WriteBinaryData('BinData', Bin, SizeOf(Bin));
    WriteString('String', 'String');
    WriteBool('Bool',True);
    Reg.WriteFloat('Float',2.366);
    CloseKey;
  finally
    Free;
  end;
end;