You may need to empty the internal hot water tank. Try powering the Keurig brewer off but keeping it plugged in. Close the lid of the cold water reservoir and put a cup on the drip tray. Press and hold the brew button to empty the hot water tank completely (there will be a delay of 3 to 5 seconds before the tank begins to drain). Then, turn your brewer back on and refill the cold water reservoir. If the Keurig still won't heat, contact their customer service at 1-866-901-BREW(2739).