no sounds from what? you never said
sure the speakers but do windows sounds work>?
and wav files dead, and did you try ear phones (or buds) at those
tiny 3.5mm phone jacks,
so all dead it is.... so...
first off XP is
not supported, ,' for 3 years.
running without SP3, is not good at all, ever. !!!
that can mean dumpster diving for good drivers,
(HP shut down XP support as did, MS)
but luck you its 2008 and dont get killed till next year.... you win.
(if savvy download all those file to a USB stick now)
so why run XP, at all,, find a used PC with w7 on it or upgrade it.
BEST SOLUTION this. baring doing this right,
Sonnys answer above.
but wait, XP will be infected, with virus , as all are..... (hopeless)
here are the full steps (if possible at all)
do F11 and reInstall XP, and Sp3 next?
or
1: using the top 5 portable virus scanners. .Eset.com is #1
clean it of all virus,
and with malwarebytes same.
2; now find what audio chip is there,
for some reason HP forgot to delete all the files. for this old DT
boy are you lucking, most this old are GONE
my guess XP 32bit. is runnng, not 64. per hp choices
make sure all device manager
if you know PC, you will know that it can take underlaying chips to work before major chips work (think'Foundation")_
so are all chips there in DM ok,?
if wise, id reload them all, and do sound last.
are some red, yellow, unknown marked.? fix them all.
see driver chip set,Id load that first (intel)
see the multimedia files, those too.
https://support.hp.com/us-en/drivers/selfservice/hp-compaq-dx2280-microtower-pc/3223349
that is it, for XP,
why run XP in year 2017 (its a hopeless virus magnet) for sure.
id put in a SSD and load W7, if all drivers can can be found.
to test a PC for W7? (applicability)
get windows PE, W7, live boot cd (or stick) make one. DL one.
boot to it and see off you have everything working. now.?? my guess is it will work. but...
see? if that works then installed W7 will work.