I have a basic-level MacBook (about 5 years old). My problem is pretty simple: when I press the power button, it doesn't turn on. Nothing happens. This is true whether or not the power cord is plugged in, and it doesn't seem to be a battery issue since I tried swapping in a battery from a functional MacBook. And it was working just fine a couple days ago. The problem is almost definitely mechanical; I'm just wondering if anyone else has had similar issues, what your best guess is as to the cause, etc. Thanks in advance for your help!