Matsui Dishwasher Noise but no action!?

My Matsui dishwasher hasn't been used for 3-4 weeks and now will not function. It makes a noise as though the motor is working but doesn't let water or anything in to begin the cycle. I read in the manual that this can happen when it isn't used regularly, however, it tells you how to prevent rather than cure this problem (by setting it to fill and drain weekly) - it doesn't say in the manual how to do this either! Help!!!