Speakers not working on any browser, but working with saved file

hi, i am using windows 8 in my pc, everything was working fine. Suddenly, one day my speakers stop working while i was playing youtube videos,interestingly my subwoofer is working at that time but not the speakers, i thought the connections were lose, so i fix that, still the problem stays, one more thing is that my spekers are fine cause they are working properly if i run any audio or video file from my saved files. The speaker are not working on browsers only(all browers like chrome, uc browser, mozilla etc), i had tried wavemapper trick but in my case the wavemapper is fine, and alot of other solutions also didn,t work for me. Please help me to fix this problem. Thanks and in advance.