Weird sound from my Lenovo T520 thinkpad(audio 626 HD) ?

Sir, I have just buy a new Lenovo T520 thinkpad 3 months ago and the device is very good. I don't have any problem while working on this new device but from last week the device giving me very weird kind of problem. When I play any file on Windows Media player, Firefox or IE (java, YouTube) etc then it provide me a very weird kind of sound. Some body tell me to sortout this problme try to use plug in a USB headset (plantronics audio 626 HD) but the problem remains same. So, can u just give me effective solution for it ? Plz help me in dis !