Water spilled on camera

First try the obvious, and press your DISP button once with the camera turned on. If that doesn't work, next thing to try would be to reseat the LCD ribbon cable into its connector. This is not too difficult, but it does require opening up your camera. But before proceeding, note that the camera still takes pictures at this moment. There is a possibility that something might go wrong, and the camera will no longer be operational after the repair. Please remember that it's ultimately your decision to proceed with a repair.

The following webpage describes disassembly of the A520/540. If you decide to repair it, only proceed as far as the first two pictures to remove and then reseat the cable. Follow the LCD ribbon cable to where it connects to the circuit board. There should be a connector with little hinge points that you lift with your fingernail to unseat the cable. Clean and dry the exposed end of the cable with a Qtip with a single drop of rubbing alcohol. After thoroughly drying, reinsert the cable into its connector and push down on the hinge points to reseat it. Then reassemble the camera:

http://photography-on-the.net/forum/showthread.php?t=251630

Also please note that there is a risk of electrical shock. Please read the following to learn how to mitigate this risk:

http://camerarepair.blogspot.com/2007/11/important-warning-camera-flash.html