How's her teeth? If her mouth hurts that might be what's causing her to not want to eat.
When my elderly dog stopped eating I first started cooking him a home cooked topper, because he stopped wanting the kibble even with canned food mixed in. That worked for awhile but eventually he lost interest in it. We went to strictly home cooking with a vitamin / mineral supplement mixed in and that worked for a few weeks, but eventually he lost interest in everything I tried. Hopefully your dog will not be the same. I just want to warn you that it's never a good sign when a former chow hound (that's what my boy was) loses interest in food.