not hearing sound internet browsers

[Kingkobra]

Hi folks,
I use both IE and Firefox to access internet . I tried to make some tweaks to my pc , something go bad and now I can't hear anything in sites like youtube....
I can play any movie, music or windows sounds but not in my browsers.

Any idea??


PD
I try uninstalling a codec pack , installing another, reinstalling the driver.
I'm using windows xp pro sp2 and all the apps running was there before it happen.

 

[Ghostman 1]

There is NO sounds in any browsers, Do you have Start and Shut down sounds??
All sounds come from your Media folder...

 

[Kingkobra]

Thanks Ghostman 1,
I have the start and shutdown sounds ok.
Some games only play effects but not music.