Windows 7: Need some help !

Yesterday when I open the computer, I go to Youtube to play a song and, speakers did not go, I play another video and the same thing. It works when I am at mozila firefox and internet explorer. Can someone help me ?

I using google chrome.

1)First restart the computer and try again.

2)Google Chrome is the only one having trouble with audio? other browsers are just fine?
Is this Youtube only? To test if it's just youtube or not please try other sites. Pandora, Soundcloud, any other site you can think of.

3)Make sure the volume is turn up on Windows Volume speaker icon.
When you click on the audio speaker icon you should see something saying "Mixer". Once you click on it find the Google Chrome application and make sure volume for this program isn't turn down.

Sorry but its not work i enter in a game after few minutes ago and the sound its work . In game yes . In youtube no.
I think the problem is from google chrome because in mozila, youtube its work
in the chrome it is not work sound of all sites

You didnt tell me if you tried all my steps?