zeph_yr :
You can't change DDR2 to DDR3 and there are no motherboards that are compatible with both. So no.
Well, I have been looking for motherboards for my old PC, and i have found motherboards made by ASrock that can use either DDR2 or DDR3 memory. Just not both at the same time.
Here is an example:
http://www.asrock.com/mb/Intel/P43C-ME/
I know, its an old mobo, but still. Just proving a point.
But in response to the original post: Can you post your current motherboard make and model, and post the one he wants to swap?