VGA to VGA cable is a better choice for you.

It doesn't work without sync even HDTV receives RGB. Only if your laptop supports YPrPb output or Sync on Green, you can use this way to connect laptop output to HDTV. Does your laptop video card support YPrPb output or Sync on Green? Does your HDTV support Sync On Green?

If not, why don't you just use a VGA cable? It is much easier.