My laptop has no sound. what's wrong with it?

Question

i turned on my laptop, and went in youtube 2 watch a vid, and noticed there was no sound, i cheked the sound bar on the video. and it was perfectly fine, so i cheked the volume icon on the taskbar, and when i clicked on it a message came that said: there are no mix devices bla bla and the icon dissappeared, so i went to the control pannel and tried from there, but when i went into the sound options icon, all the buttons where grey, and like, i couldn't press them or click on them, what's wrong?

Answer 1

just try to re install ur sound driver using the driver cd that came along with the pc  

Answer 2

check audio driver or other wise better to format once

Answer 3

Try restarting the laptop.