Video does not play sound
I can see the video but cannot hear any sound.
Please check the following.
1) PC is not set on mute.
2) Volume on the timeline is not set to 0%.
3) Other players like Windows Media Player or QuickTime Player can play them with sound.
4) Click [File]->[Options]->[Advance Setting] and see if [Enable for video playback] in [Built in codec] is ticked.
Where all the above falls in your case, you may want to install additional codecs to play sounds.
Go to the following site and install CCCP.
(This is just a reference and you need to follow the instruction CCCP provides)