Disconnect all external power and telephone wires from the computer to avoid electrical surge damage. Put computer equipment and important diskettes, CD's and DVD's, etc. into strong plastic bags. We double bag our computer equipment using strong, black plastic garbage bags. If your computer equipment does get wet, let it air dry as soon as possible. We do not recommend you try to repair your keyboard or your monitor.
Monitors can be dangerous since they maintain a charge for quite a while after being powered off.
You might want to turn those components upside-down to let gravity help get the water out. If the system unit does get damaged there is a reasonable chance the hard drive inside the system unit, or at least the data on it, is salvageable. So don't discard or turn the equipment over to your insurance company until you attempt to collect the information on the hard drive. You might want to remove the cover to the system unit so it will dry faster. The less time the water is on the equipment, the better.