Did you rehydrate and stir the yeast before you pitched it? Also, if it still isn't fermenting just give it a really good shake to get the yeast nice and dispersed. If it isn't fermenting in a few days then you might have a problem. What type of yeast did you use?
PS. If you do have dead yeast, it is no big deal. You can just re-pitch another packet of montrachet ( or whatever ). The dead yeast is actually a good nutrient for the new stuff. I am sure you will be fine, though. Just relax and have a home-brew.