how to fix my treadmill?

If your belt is not moving then your speed sensor won't be activated and that should give out a speed code.

Stand on the side of your treadmill and push the belt with your foot as if you were walking on it. Then press the start button. If Your machine starts to run by itself you may have worn brushes. If your machine doesn't start your lower control board may be bad. A worn belt and deck can kill a lower board.
Have you been maintaining the treadmill ?

If you need more help you can email me from my video sight.
www.mindbites.com/person/214-Mark

Mark Peterson
March 2008