I have recently inherited a PCV-RX401 which is working fine apart from the lack of sound. understand that a Windows XP service update caused loss of sound on this machine. However I could still get left channel sound on my headphones but nothing from the either of the integrated speakers in the monitor. Following old advice on the web I downloaded and installed what I thought was the relevant update from www.devicedriversforfree.com. Now I have no sound at all. Can someone point me to the definitive software upgrade required to fix this annoying problem. There is nothing relevant on the Sony Support website for the PCV-RX401. Thank you.