Oddly, you may find standing water at the basin of your dishwasher. Do not be too worried, yet. There are a few common causes which may lead to a quick fix. Calm down, put on your thinking cap and set aside ideas of costly repairs or replacement. (For standing water but the water drains out when you set the dishwasher to drain, see Coffee Grounds and Egg Shells in My Dishwasher)
If your dishwasher will not drain, try manually setting the dishwasher to rinse. The dishwasher should drain and refill.
If manually setting the dishwasher to drain does not get the pump to discharge and allow the dishwasher to refill, try clearing the float.
The float switch tells the dishwasher when to interrupt the fill cycle and not allow anymore water into the basin of the dishwasher. However, it also serves for another purpose, that is to tell the pump to discharge and empty water from the basin.
The float switch may be described as what appears to be an upside down cup. Often, this switch gets jammed with food particles or other debris that did not make it to the garbage can or garbage disposer. In order to clear the float, some rotate and allow you to remove the cover. Others rotate and or lift up and down. Try clearing the float. If this does not work, there may be a problem with the pump or some other aspect of relaying the message to discharge water. You will then need to call an appliance repair man. Calling a repair man is not very expensive. Most will diagnose and give you a free estimate to make the repair.
When attempting to get an appliance repair person to give you a free estimate, do ask over the phone if they offer free estimates before the technician is dispatched.