Latitude E6420 both HDMI audio and laptop audio and not working

Hi.

Some time ago I noticed that there is no audio coming out of the HDMI output in my company's Latitude E6420. I've tried different fixes that can be found by googling, but none seem to work, I did the following steps without success:

- Disabled "High definition audio device" in order to force the system use the HDMI audio output, didn't work.

- Updated the latest Nvidia NVS4200 drivers, didn't work.

- Uninstalled the "High Definition audio device" to see if it worked by chance, didn't work.

The last step made things worse, since now the speakers won't work at all, not even after reinstalling the "High definition audio device" default driver. Windows shows me the "No speakers or headphones plugged in" message. I don't really know what else should I do. I already ran the system diagnostics (from the bootup menu) and the sounds play fine.

OS: Windows 7  - 32 bit

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