First of all, sorry to ask this, I'm sure that this was asked so many times before. Second, sorry for the English, it's not my native language. And Third, thank you in advance.

So, I hope the follow info will help, here's a log. http://www.alsa-project.org/db/?f=07089caf530494bc4bc23e1d1cd56b3a5fae03c6 I already check 'System -> Preferences -> Sound'. Here's a screenshot http://i.imgur.com/Ghwnj.png

> jorge@jorge-desktop:~$ sudo lshw -class multimedia     
> *-multimedia  
>        description: Multimedia audio controller
>        product: VT8233/A/8235/8237 AC97 Audio Controller
>        vendor: VIA Technologies, Inc.
>        physical id: 11.5
>        bus info: pci@0000:00:11.5
>        version: 60
>        width: 32 bits
>        clock: 33MHz
>        capabilities: pm cap_list
>        configuration: driver=VIA 82xx Audio latency=0
>        resources: irq:22 ioport:e400(size=256)

Tried with no results:

>     sudo apt-get remove --purge alsa-base
>     sudo apt-get remove --purge pulseaudio
>     sudo apt-get clean && sudo apt-get autoremove
>     sudo apt-get install alsa-base
>     sudo apt-get install pulseaudio
>     sudo apt-get install ubuntu-desktop

Also

>     sudo gedit /etc/default/grub
> 
> from:
> 
> GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
> 
> to:
> 
> GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1"
> 
>     sudo update-grub
> 
> And Reboot... without any result.

EDIT: I made sure that everything it's fine with aplay -l and lspci -v and lsmod; and checked alsamixer, it's not in mute.

Well I'm running out of ideas.

Thanks.