Photoshop changing a colour help please!

There are many ways to change a color in Photoshop and without an image as a guide I can only guess at what you are trying to do, but here is how to change the color of an entire photograph that will work most of the time

I started with some silver coins

Now if your image is grey it may be in Greyscale so check and convert it to RGB otherwise you cannot color.

Apply a 'solid color' adjustment layer as shown

The color selection box will popup. I chose a golden-yellow

Click OK and in the 'layers' panel change the blend mode to 'color' and adjust the opacity to suit. The silver coins now become gold coins

If you want you can use 'curves' to enhance the contrast.

Obviously this method colors everything, if you want to color individual elements then things are more complex but the method will work to change a grey to something else.

Terri