My the SIMS 3 audio problem...pls help?

Im playing this game for a while now and i've accomplished many things like my sims lifetime wishes, high level gardening and fishing skills, my sims can finally cook ambrosia, big house and 3 kids 1 is young adult and the 2 others are teens but then suddenly the in-game music stopped working, i mean sometimes the in-game music plays alright but mostly all of the time its not, the buy and build mode music suddenly became mute. and the create a sim menu where i want to PLAN AN OUTFIT and CHANGE APPEARANCE in the game became mute too, the radio had also become mute and everytime a accomplish a wish' the short music for the WISH is nowhere to be heard. but everytime i open the launcher and starts the game engine to open the main menu everything is fine its music/sfx and all. but when i load and play my game all the music became mute the only sound u will hear are the voices and sfx. can anyone help me fix this problem. its kind of annoying but at least i can still play the game the only prob. is it has appearing(sometimes) and dissapearing(mostly) sound