I had similar sound not working problem on my lenovo z50-70 laptop. it was due to multiple drivers installed on my pc, so i deleted all drivers from pc and then rebooted it.
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I had similar [https://goo.gl/JRyT6e|lenovo laptop sound not working problem] . it was due to multiple drivers installed on my pc, so i deleted all drivers from pc and then rebooted it.
I had similar sound not working problem on my lenovo z50-70 laptop. it was due to multiple drivers installed on my pc, so i deleted all drivers from pc and then rebooted it.
once it came back, i got sound on my pc.