First make sure the unit is not in "control lock" causing this problem.
If the drain/spin button is held down the unit will enter control lock and nothing will respond.
If the unit is not in control lock or child lock then the most likely problem is a stuck or shorted keypad.
You can always try unplugging the unit for a few minutes and then plugging it back in.
If unplugging the unit doesn't work then you can access the control and disconnect the ribbon to the interface. The image below may help with this.
Remember to unplug the unit first.