Water or almost any other kind of liquid is not a great thing to have around your computer or any other electronic device.
This kind of damage can be expensive to either replace or to have repaired and unfortunately, many people who are unfortunate enough to have this happen to them cannot afford it.
If the liquid spilled upon the device is acidic, like soda or coffee, then it generally does more damage than simple water would do. It causes more corrosion to the metal areas of the motherboard or any other computer component such as the hard drive or CD-ROM.
One of the worst case scenarios is that you spill a liquid onto your laptop where everything, motherboard, hard drive, CD-ROM, and etcetera are all packed into the same general area.
In most cases of water damage to computers, the liquid is spilled merely on the keyboard or another outside component such as the mouse. With laptops, spilling a liquid on the keyboard does not mean that only the keyboard is affected, but also the other components sharing the shell of the laptop are, as well. What can you do if water or another liquid is spilled on your laptop?
Unplug it from the A/C adapter and remove the battery IMMEDIATELY. Unplug any other external devices including external hard drives, mice, other input devices, CD-ROMs, DVD-ROMs, and etcetera.
The next thing is to turn the laptop completely upside down to stop the liquid from sinking any further into it.
Use a towel or paper towels to clean up the spilled liquid, wipe off the keyboard, exterior, and any external devices that came into contact with the liquid as well.
At this point, you could do one of two things. You could take it to a professional repairman and have them look at it (I hope you have an extra arm and leg lying around) or if you know how to take something apart and put it back together, you can try to fix it yourself.
In trying to fix it, you may irreparably damage it, so if you are even remotely unsure about your ability to repair it, it is better to take it to a professional.
If you choose the do-it-yourself route, disassemble the computer and allow it to dry out completely for at least 24 hours, if not longer. Let it dry until you are satisfied that it is completely done.
Whatever you do, do not turn the power on before it is. It is not water itself that kills the circuit board of any electronic device, but the electricity that runs through it when someone tries to turn the device on when it is still wet.
If it was just water, drying should be all it needs. If it was soda or any other acidic liquid, clean it with rubbing alcohol and Q-tips, then put it back together and wait for the alcohol to dry. See if it works.