LG DVD drive play but no sound on cyberlink power dvd software. have idea
Try a different player and see if you get sound from it. VLC can play dvds and is free to use: www.videolan.org VLC doesn’t rely on outside codecs, so it should work.
Media Player Classic HomeCinema is also free: http://mpc-hc.sourceforge.net/
If these media players can play the dvds without issues, you should try reinstalling PowerDVD, or look for an update from Cyberlink.
If it’s an OEM version of Power DVD (that is, a version bundled with the drive) then it is probably deliberately restricted to stereo playback. So it won’t play the DTS 5.x, 6.x or whatever else fancy surround sound sound might come with the movie, and output silence.
Try selecting a stereo sound channel on the Power DVD interface, if the movie has one.