I have a prototype 15" MacBook released mid 2009. My cousin works for apple and he works on MacBooks, so he has many of them laying around in his condo. He said he would trade a MacBook pro for my iPod Touch. I was more than happy to trade with him. When he gave it to me, it had already been set up, there were no install disks. Just the laptop, charger and the box. He also told me not to upgrade my software. Later that year, I stupidly upgraded my software to Snow Leopard. It worked fine until about after a month of having it installed. I was playing a game on it and I closed the lid because I had to go. When I came back, the sound was gone completely. The speakers, headphone jack, and the startup chime did not work. I tried restarting and resetting the PRAM. I also restored it from a time machine backup, Still no luck. That was back in the Winter of 09. I bought a USB headphone jack and that allows me to have sound only through headphones. This summer, something really strange happens, the sound on the speakers comes back! I was very excited! The next morning the sound went away again. This same event has happened all throughout the summer. So, I'm guessing it might be the temperature change? And I am not 100% positive if the sound problem is a software issue or hardware issue. I have considered buying a new logic board, but I'm wondering if there is a cheaper way to fix it. Any Suggestions?