Unlock partially locked black & white

I acquired a Zip disk that has many photos that were made black & white using PS 7.0, and I cannot seem to reverse the process the original photographer used to make them the original color.

In the layers pallete, she kept the default "Background" and has the padlock icon that says it is partially locked. The history pallett has the name of the photo, and the channels has "Gray."

Am I overlooking something to reverse the process she used so that the original color pictures can appear again?

Thanks in advance!

David,

You're looking for the impossible. The image has been converted to Greyscale and will only have a single channel. They only way you can 'restore' the colour is by converting to RGB and then hand-tinting the image