You are posting in the PhotoShop Elements forum and are using full PhotoShop .. a different product and they have their own forum. You may wish to check there for a more intensive answer. Having said that, text editing is done in text layer. If, however, the layer(s) have been flattened into the image, there is no text any longer (as text anyway). It's been rasterized into the image and now is just pixels with no ability to edit as text. You'd have to edit/modify as you would any part of the raster image. Are you looking at a PSD or TIFF file? If not, then all layers have automatically been flattened upon the save and you need to see if the master file exists as a PSD or TIFF format.