How to get rid of fleas?

We have had these fleas for an extremely long time and we have tried bathing, vacuuming, and disinfecting the house but they keep coming back. We just gave the house the most major cleaning of life, including chemicals made to kill and disinfect your home from fleas, but NOW my friend had an emergency and her family had to leave the country and left the misbehaved, flea infested dog with us. Now their back and more than ever. Help us. Please. We have tried medicines, flea collars, shampoo, and sprays BUT THEY JUST WONT LEAVE!.