I occassionally connect external stereo sub woofer / speakers to my Vista laptop via a 3.5mm jacks & cable. Yesterday on doing so the laptop would not switch the sound over to the external unit but played my iTunes music through its inbuilt speakers. I swapted the external unit for another permanently attached to my XP laptop and found no change. I then played both external units over my XP laptop without any problem. It therefore seems that the problem lies with the Vista laptop and is probably a hardware issue. However I am wondering if it may be software related in that I may have managed to accidently touched a button or change a setting. I couldn't find anything useful within Control Panel Sounds and Audio Devices. Any ideas?