With the spot on flea controls the flea has to bite your dog and then it will die so I'm not crazy about this form of control. Several of them are also washed off with baths. I prefer natural remedies like 1 drop of citronella oil, 1 drop of lemon grass oil, 1 drop of tea tree oil to 1 ounce of water (also effective against ticks) and then just spritz them before going outside or a couple of times a day so they don't even have to get bit in the first place.
Most likely your carpet is full of fleas and eggs. Try cutting up a flea collar and placing a piece in your vacuum or vacuum up some flea powder. Then vacuum the whole house at least once a day. I would also treat the yard with a flea control.
Here's a good link to all the different flea control products.
http://www.naturalhealthtechniques.c...a_control1.htm