I have an Asus N551jk. I have dual boot on it. Sound works on Windows 8.1, but not on Ubuntu 14.10. More precise sometimes it works, but various events like a simple reboot, can make it not work again....
I followed the steps described here: https://askubuntu.com/questions/541880/sound-not-working-ubuntu-14-10-pulseaudio-alsa-fixed . It worked for a while, but now it doesn't work again... Not immediately sure what's the problem.
Best regards!