Wont come on or stay on

Question

I thought I possibly had a short in the cord, but a kirby salesperson passing through the complex I live in told me that there are several safety precautions on it and that it will not stay on if something is not connected properly. The machine will come on when I first plug it in and turn it on but then will go off immediately. When I began having a problem with it, it would go on and off while I was vacuuming depending on the position of the handle. I have taken it apart and checked that all parts are secure but it still wont work. Any solutions anyone.