Everybody knows that water and electricity don’t mix, yet even I sometimes forget how sneaky water really is. When water gets in your computer, it can cause two wires to short out—to send their electricity across a path the designers didn’t intend—which will temporarily disable your computer. If the short lasts long enough, it can create enough heat to melt one or more of the tiny wires in your computer, breaking that component forever.
If it were possible, I’d suggest you only used your computer in a climate-controlled room with a no-beverages sign on the door, but here are some realistic ways you can avoid moisture damage:
Keep your computer away from windows that open. Although rain falling in through the window is one threat, I once ruined a laptop by leaving it by an open window on a foggy morning.
Be extra careful with drinks and laptops. With full-sized computers, you’re only likely to ruin the keyboard when your drink spills; with laptops, you’re likely to ruin the whole computer.
Unplug the power and (for laptops) remove the battery of any computer that might get wet. It’s ok for electronics to get wet if there’s no electricity traveling through them. (When I go camping, I always store my netbook and its battery in separate zip-lock bags.)
Don’t leave computers outdoors. I know this sounds obvious, but it’s too easy to go inside to fix a drink, get distracted, and forget about your laptop—until it starts raining.