When I backed up my stuff from the old harddrive, I foolishly forgot to pack data in my important age project files in blender

Now, I was able to replace those, and only a few are still a problem. The one at hand is a texture that no matter how many times I try to re-locate it, it doesn't work! I found the texture, and changed the file path in UV Image editor, and Texture layers. Does anyone have any idea why a seemingly normal .png texture file, which opens fine when I click it, wouldn't be able to be mapped to an object again, in blender?