Our cat had fleas several times this year. Got her treated at the vet. The last time I went, they suggested using Knock Out (it's an aerosal spray can which you don't use with the pets around: they need to be out of the room for a half hour, I was told). This is a good method to use for fleas, ticks, etc. It seemed to work. He suggested I use it twice, once again in two weeks after first usage. Didn't and are good!
For people who have vaccum cleaners with a bag, change the bag after vaccuming once you start to "treat" the house for fleas. Clipa section of a flea collar off and put it in the new bag. It'll help kill remaining fleas in the tubes, and any that will enter the bag later on. Vaccum bags can be a breeding ground for fleas.
For those who have canister vaccums (bagless) the same can apply by putting a bit in the canister section.
In all instances, be aware of child safety practices though.