First check to make sure there is a bag in the machine, if so make sure that its in securely, there is a pin switch in the bag door that wont allow the machine to turn on if there is no bag in it. If that's okay, then find the knob on the top of the machine ( in the middle of the canister ) and make sure its turned to the maximum, that is a sensitivity knob that can keep the machine from working ( in case it was clogged, but if its too sensitive it could think the machine is clogged when it really isn't ).