Using the Keurig without cleaning it can get the coffee maker to not work as well. Over time the water line will need to be cleaned to allow it to run better. Using a descaling solution (white vinegar and water) and running it through the system will clean up the Keurig and it will fill the cup up all the way again. It also would help to fill the tank all the way to the top to make more coffee.
Make sure that the Keurig is plugged in, and on the back at the bottom there is a little switch you must push to turn it on. This should start your machine. If not, use a different outlet to use and push switch at bottom on back again.