I have a mid 2012 macbook pro which I bought on eBay in 2014. Since I bought it I began to get problems with the power management of the laptop. For isntance, I would shut down the computer, and it would just not turn back on for a few days. This happened multiple times and I've taken it to the genius bar and they offered to do a full test and see what was wrong. The test turned out that nothing was wrong, and it worked fine for a little while. Also, the genius bar person let me know that in fact, the previous owner also had this problem (thanks eBay!). Now, a week ago it happened again - but this time it wouldn't come back on for 5 days so I called up apple support, and even though it was out of warranty they offered to get it repaired for free. I sent it off to an apple approved technician and they called me and said when it arrived it had turned back on fine, and he was running tests and found nothing. But he said whilst turning on the computer he found that the power management had become corrupt and that a usb cable can cause this, and said when the battery goes to 0 charge it can then be recharged and turned on (and battery must have gone to 0 during the delivery). He said it is usually due to a usb cable of some sort but I have never plugged a usb into my laptop, and certainly not in the past few months. He said he didn't know what else it could be. I asked him to keep testing it for a few more days and if he finds nothing to send it back. Now, I'm almost certain he wont find anything but this problem will continue to happen. I have already reinstalled the operating system, looked up how to take care of the power management online, replaced the charger etc. I have no idea what to do if it happens again - this is extremely annoying as it means my macbook isn't reliable. Does anyone have any advice on how to fix this - I want to get a replacement, but that's obviously not an option. I need this laptop for my computer science classes and I cannot for the life of me gather enough money even for a cheap netbook. Any advice, thank you.