Replaced both elements, thermostat, pop-off valve, drained my tank and still no HOT WATER..what Next?

If power to the heater was turned back on before it was filled with water than the elements will be burned out. They have to be immersed in water before they are energized. Is it cold water coming out of the hot water spigots or no water?. If it's only cold water coming out the hot side, than it can only be 1 0f 4 things. The elements are bad, The lower thermostat is bad, The upper thermostat is bad, or there is no electricity coming to the heater. If your tank is not leaking, I would not buy a new one because the cost of a new one is considerably higher than all the parts that could be bad cost total. If there is no water coming out of the hot water side than it may be a valve thats been cut off in-line that wasn't turned back on. I've never heard of scale building up so much that no water at all will come through. I've also never heard of blowing out or flushing out water lines because of lime.