Photoshop :: Dropping Out A Background

I have been using Photoshop since 1989 when it was a proprietary software developed for the long-gone Barneyscan. Even did a book about whaling in Hawai?i using what by then was an alpha version of Photoshop. Still I am, without question, a newbie, as I only use it for very specific tasks involved with designing books?primarily cropping, correcting flaws and color balancing of historic photos. I am using a Mac G4 running Photoshop 7.0

I have a book going off to press?supposedly yesterday?but I have spent hours trying to do what I am sure is a simple task . . . eliminating a background entirely. I have about thirty of these to do and am getting desperate. Here?s the scenario for one, and if I learn the step-by-step, it will work on all the rest. I have an old Matson Navigation logo which is round but was sent to me within a square. It has, in other words, a gray box around it. I want to place the round logo only?without the box?on a photo in InDesign.

Here is how far I have gotten:

Open the file and size the logo. Done.

Go to Layer> Duplicate Layer> Background copy. Done.

Go to Layer> Delete> Layer> Original Background. Done.

Using Magic Wand> Click on box around circle logo. Hit delete key.

Result is gray checkered background.

Using Magic Wand, click on checkered background to trigger marching ants.

Go to Select> Inverse.

I have what I want?just the logo. I need to figure out the last step in Photoshop so that I can save it as a round object only and then Place it in InDesign.