Layer issue: Layer isn't working correctly anymore. First I put in background, then a few other layers. Each time I add a layer, I canNOT go back to work on a previous layer. How do I return things to normal? Thank you!

I create my own book covers. I start with a background and add people or objects, and finally text. In other words, I layer the cover. All of a sudden, after creating several covers, I can only work with the most current layer. The program will now allow me to go back and change or move an object. What can I do? I'm having to recreate each book cover from scratch. I'm using Photoshop Elements 8, if that helps.

I thought about just reinstalling the program, but if I do that I'll lose all the photos and images I have. Sorry, I'm not very techie.

Thank you!