This depends on your motherboard. Some motherboards have short protection, so when they detect a short, they shutdown, though this feature is typically designed for when the pc first powers on, not for when it is already running. So long as you have not damaged any components (capacitors are the most common type in this situation), the board will work fine when the water is gone, but the faster the water is dissipated, the better the chances. Many people will use silicon packets to pull excess liquid, some will use penetrating fluid such as WD-40 to lift and remove water. Just don't use a hair dryer or any sort of towel.
Now if you have a blown or distended capacitor or have damaged anything else as a result of the liquid spill, either the component or the board itself will need to be replaced.