Your problem is common for all 2100 series as well as LE models. There is a broken plastic part holding a spring located under the plastic button that you push down on to start your vacuum. It is an inexpensive part, but is a little difficult to change.
First make sure that the cord is unpluged from the wall and is completely back in the cordwinder. Next, remove the hose and bag from it. With the bag door open, place a medium flat screwdriver between the rear rubber bumper and the back plastic end cap of the vacuum.
Do not try to pry the back cover off, you will only break it!
With the screwdriver placed on the rear bumper, use a small hammer to strike the screwdriver shaft toward the front of the bag door. The rubber bumper will slide forward. Repeat the process with the other side. After removing the bumpers, the top will lift off with a little wiggling.
Pay attention to the slots in the covers that the motor sits in so that you get it back in the same slots. There a 2 screws holding the switch and the plastic part that is broken located on the underside the top cover of the sweeper.
Replace the plastic part and assemble in reverse order. It is tricky to get back togeather.
Good Luck
Captaintek, April 2010