Tried everything, but still no sound in Ubuntu 12.04

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http://askubuntu.com – I have tried killing pulseaudio. I have tried editing alsa-base.conf. I have tried alsamixer. I have tried uninstalling and reinstalling alsa-base and pulseaudio. I have tried everything I could find, but still no sound. My computer is an HP Pavilion dv6 6190us with switchable AMD and Intel graphics. The sound stopped working suddenly after an update. Pavucontrol shows that I am outputting audio in that progress-bar sort of thing, but I can't hear anything. Even headphones/external speakers don't work. I can change volume using my volume keys, but nothing happens. Please help. I am a linu (HowTos)