CS5 - the background layer - although it shows as being locked - it is not -- when I add a new layer the new information also changes in the background layer - how do you fix that?
Can you describe in more detail what you mean by "the new information also changes in the background layer". Maybe provide some screen captures if you have trouble explaining in detail what you're doing.
I suspect you're misinterpreting what you're seeing, but without more specifics about what you're doing there's no way to give more specific help.
Cropping affects all layers in the document. That's by design.
You can have Photoshop preserve the pixels (out of sight) by choosing the Hide pixels option when cropping:
Other options that come to mind are to make a new document to work on the smaller image in, or to use a selection and delete the frame from around the edges (or mask it) on Layer 1.