black screen, computer won´t start up

Last night we opened our Macbook Air, and only got a black screen,it wouldn´t start up. After fiddling with it awhile, it came on. My husband said that he just tilted the screen forward a little bit, but that might have just been a coincidence. What can we do.

I will say, but this might not have anything to do with it, that we spilled water on the keyboard about a month ago, but immediately shut it down, dried with a towel, and used the fan trick to dry it out for at least 2 days, and have had absolutely no problems with the laptop since.

Please help! We´re out of country and don´t know of anyone who could fix this here!