GET BACK YOUR BACKGROUND LAYER

Lost your Background layer? It happens. It's heartbreaking, but it happens. If you suddenly find yourself staring at a Layers palette and there's no Background layer (chances are you accidentally converted your Background layer into a regular layer), here's how to get a Background layer again: Create a new blank layer. Then, go under the Layer menu, under New, and choose Background from Layer, and Photoshop will take your new blank layer and create a solid white Background layer at the bottom of your layer stack.