No, swapping the cpu will not solve the problem. The cpu is the "central processing unit" all your xbox info is stored in the nand. So what you need to do is get a non banned xbox360 and dump the nand from it and flash the new nand to the banned xbox. But really the process is pointless because you might as well use the unbanned xbox. The only point i see to this nand swapping is if you have a jtag and you host modded lobbies.