I'm confused. The ATI Xpress 200 is a chipset found on the motherboard not a CPU. So you would be replacing the motherboard, then you would need an AMD Athlon/Sempron processor (CPU) to go with it.
But if the motherboard fits and the power supply is capable there is no reason you couldn't drop it in the e-machines case.
^sorry wrote that wrong but what im saying is can i take that cpu and replace mine 2 get more ghz or is it not possible sense its a dual core im trying to put in my comp?