that chip maker went BUST, conexant in 2013, loss of Kodak contracts killed it (camera film end of life)
HOW EVER.
hp may still have it. (they do.)
HP only supports VISTA on this PC, period.
and there are no w7 conexant drivers there
but if googled vast sites have them full of VIRUSes
the cure is USB sound card dongle that does support w7
there are 3 drivers the for your 6915nr
2 for
conexant
1 for ,
realtek
this PC was sold in many versions some used the realtek chip
that is why at HP.com the demand your service tag data
and product number, t<<< this whose sub models and country too.
all very different PCs.
here is 1 cure,
learn to run HWINFO32.EXE FOR FREE
SEE WHAT SOUND CHIP IS REALLY THERE.
THEN LOAD THAT. NND ONLY THAT. SOUND DRIVER.
AND VISTA DRIVERS DO NO WORK ON W7 OR ARE 1/2 DEAD OR WORSE.
W7 DOES NOT BELONG HERE. SORRY BUT THAT is how the cookie crumbles.
wiki facts
"On July 26, 2017, Synaptics completed its acquisition of Conexant Systems, LLC.
[19]
By November 2017, Conexant.com was no longer available.
Synaptics provided no information about what it did with the website.
[20]" << sucked into the BLACK_HOLE
the latter ended all support.
HP, your page is here, read it at all, see AUDIO.
https://support.hp.com/us-en/drivers/selfservice/hp-pavilion-dv6900-entertainment-notebook-pc-series/3725196/model/3740557
also dead is N_force chip sets so is double dead.
also some other chips dead as you will discover... full stop ,me.