If you are going to a totally different model, you will probably have issues booting, and will probably need to re-activate Windows. Read this http://arstechnica.com/gadgets/2007/09/how-to-install-a-new-motherboard-without-reinstalling-windows/
If you are going to a totally different model, you will probably have issues booting, and will probably need to re-activate Windows. Read this http://arstechnica.com/gadgets/2007/09/how-to-install-a-new-motherboard-without-reinstalling-windows/