i was getting issue of no sound. i tried all solutions over the internet but nothing worked. Reinstall realtek audio drivers many time but never worked.finally rebooted in safe mode and then rebooted in normal mode. And sound started working. i think it was the IRQ conflict issue. probably two devices were sharing the same IRQ. since safe mode boot does not load any drivers and released the conflict of IRQ. in next reboot all devices got new IRQ.