treadmill problem?

We have a sportscraft tx400 treadmill. It has started to stop unexpectedly in the middle of my treadmill session. It did that several times. Now it seems to run fine, until I step on it and then it goes very, very slow. I called the place where we purchased our used treadmill and they said either there is a wax or a silicone coating between the base and the belt. It sounds like this might be the problem, but I need to find out if I should get silicone or wax, and how do I take it apart to apply it. I really don't want to purchase another treadmill, if there is something that can be done.