Dora Sound Clip I Cant Get Any Sound From Sites I Go On To.HELP!?

I cant get any sound from sites I go on to.HELP!? - dora sound clip

I think I accidentally changed some settings in some way ... Before he could get, while the audio and video clips played a particular site .... Now give me a single clip ... and no noise .. What can I do? .. I wanted to see and hear the song Soldier Boy Dora Explorer U-tube .. Sorry Soulja Boy ... and I'm gone, but I have not heard. This is not my system because I can run Media Player and make it sounds ... What I did .. Help ..