I know it's not the power adapter that's disfunctioning because I tested it on other computers and it worked fine. I tried removing the battery, holding the power button down for five seconds, removing the battery and simply plugging in the power adapter, and even charging it with some one else's power adapter (Not to mention that I tested about 20 outlets). None of these worked. Apple tells me that it will cost me $800 to fix it if they determine that it's not a manufacturing defect so I do not want to send it to them in case it is some other kind of damage. I am not sure what damaged it but I suspect water damage.
What should I do to fix this? Thank you so much!