Why does it shut down after booting?

Today I committed one of the worst offences to my Mac: I spilt coffee all over the keyboard. Thankfully it was still functioning. I cleaned it up and immediately shut it down. I vacuumed the keys and left it sitting upside down to dry out.

It seems to function smoothly minus a couple of problems. Firstly, I can't power it on via the power button. Instead, I close and open the lid which turns it on by itself. Secondly, a few seconds after completely booting up, the message "Are you sure you want to shut down your computer now?" appears with the various shut down options and then it automatically shuts down no matter what.

Any suggestions would be greatly appreciated.