lost audio on HP DV6700 laptop since upgrading to W10

lost audio on HP DV6700 laptop since upgrading to Windows 10

have removed sound device from device manager and reinstalled, have replaced driver with previously saved W7 driver....still nothing, not even the windows system sounds, critical battery etc....

all seems eps ok except this.....saw a post that says the sound is integrated with the graphic card, but the graphic card now has a windows 10 driver from nvidea.....maybe should downgrade GPU with W7 driver...

any my thoughts please ?

UPDATE....
just tried the idea of setting frequency to 16bit 9600 but I received no sound output error box....then went to enhancements settings where it has bass etc etc settings, was disabled so enabled it without choosing any option..then went back to frequency and changed it to default, which is 24 bit 19200....then was told not supported by this device but then miraculously it worked....now have all sound restored windows music everything...not sure if still have windows 7 driver...it is MS 2008... really scared to update the driver as it is all now working....not sure how I fixed it though, was it one particular action ? or a combination...? maybe it might help,others...

Lost sound again, uninstalled soundcard, will not reinstall and tried installing drivers from hp website but said no device found

help please