Edit of 27/10/2012:
After a few weeks of using a bug appeared. After much research on the web, it turns out that he is related to the use of a Crucial M4 SSD on which my system is installed.
Overnight you turn on your PC and there no longer comes out of your speakers ... To date did not found any other solution than to just uninstall and reinstall everything. The problem occurs regularly, quite unpredictable.
There is no updated driver for this purpose nor for the SSD, or to the sound card.
For this, I'll withdraw two stars on the five initially allocated ...