Hi there! Perhaps not the best place for this particular question . . . .
Dumb question - is your sound muted?

Try Win XP's system restore; Start | All Programs | Accesories | System Tools | SSystem Restore
Sony's site *should* have what you need, you'll probably need to dig a bit more.
To identify your hardware, Hit [Win Key]+ [Pause] to bring up System Properties (or Start | Control Panel | System ). Select the Hardware Tab, then Device Manager. You'll probably see the Tree or Outline view of your system devices expanded - if there is a problem.
Finally,
http://driverguide.comhope this helps - john