I have a sony led with 2.1 sount output bt i buy a sony 5.1 hometheatre how to change my 2.1 sound to 5.1 surround sound
You will need nothing short of a magic wand.
You can't. Most tv channels are recording in 2ch stereo so 5ch will not work. Generally on movies and games are 5.1 so your options will be to buy a source like bluray player or games console if you want true 5.1 performance.