There is a recall for your computer. Call apple they will help you! Otherwise it could be anything, hard drive or CPU! Tell us what computer you have and then we can help you. On most models you can find out what computer it is be going to the apple logo on the top left hand corner of your computer, then press about this mac. Get back to us when your done!
Hi, I had this same issue with my iphone 5c. It turns out that it is to do with the antenna that is near your battery. I suggest taking it out and putting it back in again. Please also clean it! So many people get it wrong but your oils from your finger can mess up the system, clean it with windex (not too much though). Also going back to your question the best place to buy is either gumtree or ebay. If you want a trusty motherboard for a little bit more money I would get if from here! At least you know it wont break. Please help me as well. Questions and comments on my page: Iphone 4 does not turn on after getting to step 9 on replacing screen, it might have something to do with the cable however I don't know. Thanks, Max