You haven't given much to go on - no-one on here is psychic!
If you load the 'Audio effects.capx' that comes with C2, can you hear anything when previewed? If not, then can hear ANY sounds at all, outside of C2?
What browsers are you trying?
Try and give as much info as you can, or the responses for help are just guesswork.
If your vision so exceeds your ability, then look to something closer.