The Ninja blender is picky. Make sure the lid is on with the spout directly opposite from the handle. And if the lid is not locked down completely, the power button will flash red and not start. ALSO... make sure the pitcher of the blender is on the base correctly. It will fit onto the base in any position, but if it is very difficult to rotate the pitcher into a locked position, it is not on correctly. The pitcher should rotate on the base with very little effort.