Default [Q] No sound

Galaxy Nexus I9250

Sorry sir, im new here...i want to ask for update....why my phone no sound in music, games, or other media such as you****.. but when i plug in headset the sound come out. in previous update hmmm 4.2 beta 3 is fine sound in speaker or headset no problem.. can you tell me how to fix it?

sorry for bad english