White Knight reverseTumble Dryer Model C44AW. Need help PLEASE!?

I put in my washing pressed start and nothing happened. I checked the start switch and it didn't work so I bought a new switch and replaced it and switched it on and the dryer worked. Well pleased with myself I put the top back on and pushed the dryer into its cubby hole put in my wet washing and added a dryer ball, closed the door and switched on and everything worked perfectly. So with a smile on my face made a cuppa and went for a sit down. Approx 15 min later I went back into the kitchen and it'd stopped and wouldn't work. HELP!