If the motherboard doesn't change then you shouldn't need to redo Windows. Do one change at a time, so that if you do have any side effects you will be better able to understand them. Update your BIOS to the latest revision BEFORE your CPU update. If you are swapping from AMD to NVIDIA (or vice-versa) make sure you uninstall the video driver and reboot to get back to the basic video driver BEFORE swapping cards.