See how I troubleshot a treadmill that was not working. The repair attempt ultimately fails, but it may be helpful in showing what I learned. Check the circuit board and the motor to find what is not functioning.
If you need a new treadmill - guess what, Amazon sells them:
US: http://amzn.to/1OVivfp
Canada: http://www.amazon.ca/s/ref=as_li_ss_t...
UK: http://www.amazon.co.uk/s/ref=as_li_s...
Remember - SAFETY IS IMPORTANT - don't mess around electricity if you don't know what you are doing. I'm not responsible for your actions.