So my sister just bought an open-box mid-2013 11" MacBook Air from Best Buy today at an amazing price. The salesperson said someone had returned it because he just wanted "more memory," but we can't be sure if the clerk knew that for sure or just made up that answer. The machine was released 2 months ago, so it can't have been used for too long. Upon visual inspection, the exterior of the machine looks flawless. But she wants to be sure about the internal hardware. Specifically, what should we look for/test to make sure everything is in working order. She's got 15 days to decide whether to keep it. Any help/advice/pointers would be greatly appreciated. So far, we did a Youtube dead pixel test, and didn't see any dead pixels. We also checked all the USB ports and the headphone outlet to make sure they're working. (We don't have any Thunderbolt accessories to test the TB port).