When our rental home became infested with fleas, I pulled up all the carpet (it was shot anyway). Daily, I washed all the wood flooring with VERY hot water with bleach added. This got into the tiny spaces between the boards and under the floor molding. I kept this up for about a month, then once a week. I had successfully killed off the fleas and the larvae throughout the house and never had another problem as long as I washed all the flooring each week.
Also, if you sprinkle salt on carpeting, you must vacuum every couple days with moth balls in your vacuum bag and disposing of the bag right after vacuuming. Fleas occur in cycles so you may get the live fleas knocked down but if you don't keep up with the vacuuming, and reappyling the salt every few days another bunch of flea eggs will turn to larvae, then to adult fleas. Your pets should also have fewer fleas.
Doing this along with using Frontline, Bio-Spot, whatever should get fleas under control. You must put in the time and hard work to break the cycle but then do the maintenance cycle frequently.
By Mary from Victorville, CA