Constant Shut down message

My Mac book Air (Mid 2012) wants to shut down all the time. Every 2 mins or so the message, "Do you want to shut down etc." comes up with the usual options of Restart/Sleep/ShutDown or Cancel. I click on cancel and the message box goes away for 1-2 mins and then pops up again. If I do not select any options it will shut down.

My kids spilled some water on the keyboard a few months ago, but the message just started appearing now. I read a few posts saying it could be the keyboard. So i replaced the keyboard and the problem is still there..

I did the SMC reset and all that did was make the fan come on once I started the laptop.

Did some more reading and now it appears it may be the logic board. I don't have a problem buying and installing a new logic board , but I don't want to spend more money and it not fix the problem..

No, I have not taken it to the 'Genius' bar yet.

Sorry for the long winded question.