Answer to: MacBookPro does not power up on AC power or battery.Make sure you have the right power supply. The MacBook Pro uses 85W power adapters. The MacBook and MacBook Air use 60W power adapters. I had a 60W adapter. That's why my MacBook Pro didn't start. You can find the wattage listed on the power adapter. If the wattage marking has worn off, you can figure it out by multiplying the voltage by the amperage, like this: V = 16.5V A = 3.65 16.5 x 3.65 = 60.225W So, it was a 60W adapter I was using, which was the wrong type of adapter.