do not have USB headphones connected, now, or it will fail ! (ask)
you forgot to NO SOUND FROM INTERNAL speakers.
not magically, XP is now dead. your PC runs XP or VISTA
that are both dead now, MS does not support them,
that means if driver goes missing (lots of ways, no need guess them here) but are now gone, your PC cant get them from MS now because they (MS) shut down the PnP servers. (means no drivers)
VISTA went to NO SUPPORT spring 2017, a fact.
its and old PC, why not reload the OS, windows, from you original disks.? or try the F11 key ,at power on (recovery)?
this pc was made in the year 2007, and has some support still.
how lucky you, most this old HP drops support.totally.
HP does not sell install media this old though if F11 fails.
NOw your official support pages at HP next:
HP says it came with VISTA, is VISTA still there??? we cant help
you at ALL lacking that critical factor.
but lets pretend you did say VISTA
. 32bit (click control panel, then pick system
icon, read what you own there)
so click this. vista 32
see that sound driver there,? sure, run this. driver intaller
from HP, this and only this works, Vista 32
that is all there is. on Conexant chips.(sound/audio)
for this PC, but do know that other driver must be good too or the sound chip can fail. (for sure the one marked "chipset")
reload them all but do not do
MODEM or BIOS
try the first 4 on that page. to get sound. working.
do not run XP drivers on Vista that is hopeless as can be.
did you know 99% of the drivers web sites you see
are full of virus or wrong drivers, or both.
do not use those.
use HP drivers.
the chip maker was bought out and no support now.
see what I mean by zero support for old things?
Not only that but your PC can be virus infected and sound dead is the least of the worries.