9 times out of 10 its software but a pci or scuzzy soundcard can sometimes make that happen as well.
In any event I'd uninstall all sound audio i.e. media-player, itunes, chrome and VLC then put one (
only) back on...
p.s. For whats its worth I use "
Zoom Player FREE" on my xp machine because its free and and very compatable with all my systems... I have xp, 7 64bit/ 32 bit, 8 & 8.1 running itunes.