Doesn't drain all the water the first tim...

if its over filling i would first check the float switch in side the dishwasher. its most likely sticking and allowing it to over fill. with out knowing your make and model it hard to say where to go, but the most common ones are on the inside and are under a cover that usually pops off. go online and try to find a schematic of your model and locate the float switch and then start by cleaning it up there may be some food or soap build up on it.