Dishes wont clean

Depending on the type of the machine, there is a sump (depressed area) in the bottom where the water is drawn into the pump. You need to clean it out. There is a screen or cover over it that can be removed. This is where a lot of the debris goes. The other thing is that it might be the jets on the spraybar are plugged with food and last but not least the pump might be shot.

Have you run out of salt and/or rinse aid?