What is the matter with my dishwasher model 302?

My Electrolux dishlex 302 won't go. I press the start button,and pick the program "quick30", then the start button. The P starts to flash so I press start/pause button and nothing happens. I then press the program button and go through to quick30 once again. It starts to make the right noise as though it is going to start washing, then suddenly stops. I left it off for a while, and tried again, however the same thing happened. Please help.