Selecting pixels

Please can somebody assist. I have a trial edition of Photoshop Elements and have been playing with Layers. After selecting an area with a border marquee I am unable to Layer via copy or cut. An error message reads "Could not make a new layer from this selection, because no pixels were selected."
Many thanks.
Sean

Sean,
It's probably that you have the wrong layer selected in the Layers palette. For example, in the Background layer you select a person's head and copy it to a new layer, named Layer 1. Then immediately you select a second person's head and try to copy. In the palette Layer 1 is selected so you get the error message. Switch to the Background layer and do the copy.