realtek soundcard is not working
 

I am using ubuntu 10.04, where my realtek soundcard had been working. but for a few days it is not woring. I am sure my speakers are on", when ubuntu is started, but no starting music. I found nothing in mute mode. How can i find the error?

make sure your speakers are on, plugged in, the keyboard mute button isnt on etc, then

https://help.ubuntu.com/community/SoundTroubleshooting