Desktop Audio

The envy has been relativly trouuble free up until a week ago after a windows up grade though not immediate say a day or so it wouldnt boot up start propblem it said  the only thing I could do was restore to before upgrade.  everything came back end of story.  week later I think it reinstalled windows update, let it go .  no problem for several days until today .  I was in the computer playing microsoft solataire game when I noticed no sound.  so I rebooted firgure shake it loose.  nothing, kept getting cant find device, when I tried to upgrade driver it would kick back found new driver but couldnt install it.  I went all the way to removing diriver totally and letting windows reinstall to no avail no change.  I even defaulted the bios and that is where I am now.  The only thing that bios move did was clear idt high definition audio codec caution sign.  now in device manager when I click on the IDT High Definition Audio CODEC this is what I get. No drivers are installed for this device., manufacturer unknow. I am streached to my limit any help would be of course greatly appreciated.

Wayne