I am running PSE 11 on a Macbook pro with OS lion 10.7.5.
I started with PSE 11 a few days ago and things were fine. Now a file I have been working on has problems. I can cut, but can't paste (only paste into selection), also I can turn on the grid, but not the ruler. It does not happen with new files I open, but it has with some that I have already worked on. I was saving my work as PSEs.
Even when I deselect it does not work.
I think the problem was that I saving them as PSE and PSD files. Just experimenting with it, it seems the ruler and paste are still available when I save things as a PSD.
Now I need to figure out if there is a way to recover all the work I did on other files saved as PSEs.
I did not mention that I can not select any of the modes. I can put the arrow on expert, but can't select it. The same with the create button, I can't choose any of the drop down menus.
You said that you had saved your work as PSEs files - my understanding is that these files are project files and contain pointers and information about images and do not actually contain an image themselves. If you open a PSEs file you can continue to work on the project with the limited tools for that project.
The main purpose of the project is usually to print out a collage or similar and so the output is usually to a printer.
If you are trying to merge parts of one image into another to form a new image, there are ways to do it.
Sorry if you know all this, but if you let us know what you are trying to do, someone like Barbara will be able to point you in the right direction.