Water gets in anywhere. No matter how well sealed your laptop is liquid always manages to get in. Liquid ingress will start causing damage very quickly, and it does not take much. The photo above is an example of what iLogix Computer Solutions see regularly on computer motherboards. This one in particular is from a MacBook Pro Logicboard. In this case liquid has started to cause corrosion around some capacitors which eventually introduced a short circuit that prevented the Mac from powering on. The client contacted us and told us her Mac would not boot, obviously she had no idea that this had happened. She was completely unaware that her Mac had come into contact with liquid.