1999 Honda Accord Engine Over Heating

My car has been turned up regularly and has run fine until a couple of days ago where out of no where the car starts to over heat. I noticed that the fans did not come on like they were suppose to when the car gets too hot, however the fans did come on when I turned the a/c on. The do it selfer I am, I tired to fix the problem myself. First I replaced the sensor and switch and the car still over heated. So then I replaced the thermostat thinking, I fixed the problem but I soon found out the car was still over heating. Thinking the radiator might be clogged, I replaced it and burped and primed it and the car is still over heating. My friends are telling me that it might be a blown head gasket, but the engine sounds nice and it sounds like it is running on all cylinders. What do you guys think the problem could be? Thanks for your time, hope to hear from you soon, before my wife takes it to a shop!