Here are three images. The first is a picture of my Christmas tree totally out of focus (Bokeh). The second is the same shot but in focus. The third shot is a merge of the first two.
I loaded the first two images into PSP9. I copied the second image to the clipboard and then closed it. Going back to the first image, I did a "paste as layer". I then reduced the transparency of the new layer to about 50% and merged. You see the result in the third image.
This may be old hat to many of you but it took me a half hour to figure out how to get the second image as a layer in the first. Now that I have that figured out, a whole new world of ideas awaits!