Underbody Shield problems of the 1996 Ford Taurus

I noticed a clicking in front end when turning,stopping and accelerating wich very quickly graduated to a loud popping sound. After taking it in to the garage they found that the half shaft and tie rod were damaged on front passenger side. After replacing the parts it was still popping. They put it on a hoist and realized that the frame was completely rotted away at the front passenger side of vehicle. This was imediately declared to be the cause of the damage to the half shaft and tie rod. After taking it to another mechanic to repair the damage to the frame, he noticed that the floor was near completely rotted out as well. I have a friend that has the same car (model and year) and he is having the exact same problems with his car.