3000GT VR4 Help

Ok my car is overheating like a B!@7H so i cant drive it. I replaced the Thermastat... Its full of coolant... no leaks... both fans work... what can it be? and to add when I start up my car white smoke comes out but then it stops... but it was doing to befor it started overheating... thats the only 2 problems with it... can i get some info on whats wrong...?

Is the white smoke coming out of the exhaust or the engine bay?

bad water pump maybe :dunno:

probably what he said ^^