Can i use existing LG Surround Sound system (LHT550TB) with a new blu ray dvd player? is it just a case of swapping the two dvd players over? does it need to be an LG player?

component video output is not going to help you hook it up to a surround system. component video is just that - video. No audio signal is carried on it. You would be better served hooking your blu-ray player to the tv via hdmi cable and then running an optical cable from either your blu-ray player or your tv to the surround system (assuming your surround system has an optical input).

That shouldn't happen, what kind of cable are you using? you should try an hdmi cable. its electronic so it either works or doesn't and there shouldn't be any lag at all.

http://www.ehow.com/how_5005144_connect-box-surround-sound-system.html

Depending on if your surround system has a hdmi input or not. if it does you can connect the blu-ray player to it. If it doesn't have an hdmi input you will have to run the hdmi cable from the blu-ray to the tv then run a set of rca cables (red and white plugs) from the tv audio out to the surround systems' audio input jacks to get sound through the surround system. Most surround systems don't have an auxiliary input for another video device.

Your LG tv should have an optical output socket,if your surround system has one as well,(input) then connect an optical lead from the tv to the system,then select either input 1 or opti 1(depending on your system) you will then get the sound from whatever you are watching on the tv

as far as hooking up your blu ray player to the sc-pt660, the only real way to utilize the surround sound (with true surround sound) is through the optical audio out. You need to connect your blu ray player through hdmi to your tv and then connect your blu ray player to your surround sound using the optical audio out/in. I, personally have the sc-pt660 hooked up through component cables so I don't waste an HDMI input on my TV. Except for cd's, there is no reason for you to use the actual dvd player part of the surround sound considering you have a blu ray player. In conclusion, hooking your blu ray player and the sc-pt660 up to get better video simply isnt possible (your blu ray player alone gives the best possible resolution, 1080p). As far as audio goes, run an optical audio cable from your blu ray player to your sc-pt660 to get true surround sound.

You say this doesn't happen on regular cable or when playing a regular DVD. Hmm. Is this Blu-Ray player connected by simplink? HDMI is a bi-directional format cable, so  there are cases in setups where your tv can send commands to your blu-ray player and vice versa. It could be a problem with your blu-ray player that it is sending for some odd reason a mute command to your tv. Or is processing a command that your TV interprets to be a mute command when playing blu-rays. Because if it was the TV itself chances are you'd see this when watching a normal DVD or on cable as well. Since you say you're not, it leads me to believe the issue lies with the blu-ray player itself. 

If it does it with just the one disc it is probably the file that you burned. Does the file sound ok on the computer? Sometimes files that are downloaded have bad audio tracks and I have seen cases where the encoding software that you are using messes up the file when it is modifying the file.
Try another DVD or Blu-Ray disc and see if it still distorts. If it does then it may be a setting in the player or in the receiver.

Cheers

Unfortunately because your existing system does not have the option of connecting an external source, such as another DVD player, the only option you have is to reuse your existing speakers and purchase another amplifier. Trying to patch another DVD into your existing unit would require a bit of technical expertise which would be more trouble than it is worth. The all-in one concept is convenient but very limiting in terms of expansion.

I couldnt get the blue ray format of kung fu panda to play in my sony blue ray dvd player. the previews and the menu screen run properly, but when i push play movie, it shuts down the dvd player. can anyone help?