I have a Nintendo Wii and a Dell 2405FPW 24-inch LCD monitor. The Wii comes with one of those red/yellow/white three headed cables which plugs in to my monitor just fine – but I can’t figure out how to get sound. It seems that the red and white cables are for audio – there are sockets for them on the monitor, but I can’t work out how to wire my external speakers up to the monitor or to the Wii. What do I need to do?