My mom and dad used Frontline on their cats, but the one cat has an allergy to it, and so they switched hers to Revolution. She's been good since. Just so you know that they aren't all alike, and if she gets a reaction from it, there are options.

Be sure you vacuum really really well in your house. If there were fleas, there are eggs. The eggs will hatch, and you'll have more fleas. And even if they don't bite Snow anymore, because of the Advantage (if you KEEP using it), they can still bite you. Advantage, or any other flea medicine, is not once and done. You have to make sure the rest are gone, exterminating if necessary. You don't want to be infested in the house, because that can be really bad!!!