There I was, in the conference room setting up for a presentation. I needed sound for a clip within my Keynote presentation. They had one of those mounted overhead projectors all wired up with sound. I reached behind the Windows machine and unplugged the audio and video cables and plugged them into my MacBook. The video came up, but no sound. Beads of sweat formed on my brow as I tried in vain to get sound out of that system. The presentation was set to start in less than 10 minutes and some early birds had already arrived. Read on to find out what I did.