Maytag Quiet Series 300 won't wash and spray water

My Maytag Quiet Series 300 won't washing. The water can come in and come out. After filling the water, the motor have noise like it is working. but when i open the door very quick and only see few water come out from the bottom spray arm, no water from top spray arm. then i close the door and the water won't come out any more. I disassemble all parts above the motor and try to clean it. still the same problem. The filter screen inside is dirty and i do not know how to open and clean it? could be the filter screen cause the problem (How can i know if the filter screen cause the problem) or the motor has the problem?
thanks