The wife let the battery run down on her Macbook Air. Then the thing would not take a charge and would not start up. She took it to the Apple Genius Bar where they told her that there was water damage and the repair estimate is $750. They even brought the back of the computer out with 1 drop of liquid to show the "water damage. They said she should buy a new computer. Well. that didn't sit well with us. So, I found the proper tools and took the thing apart myself and guess what, no water damage. I have taught Electrical Engineering for 30 years and I know water damage when I see it and there was no damage here. I did determine that the battery was FUBAR and I set about to find a new (used) one. Hence iFixit to the rescue:)
Put in the battery, charged it up, and voila, everything worked fine.
The actions of the tech at the Apple Genius Bar was FRAUDULENT. The tech put water on the back of the computer and fabricated the "water damage" story so they could sell a new computer. I (we) will NEVER trust the Apple Genius Bar again!