you use the uninstall program to remove the hardware drivers (there are also 3rd party programs and manual methods to do this as well). shut down, install the new hardware. windows detects it. install the appropriate drivers, reboot, and you're done.
you're at your "full" potential.
the only reason to start from scratch is if you don't know how to properly remove remnants of apps/drivers left over from removed hardware/software.
as for your cpu example, you simply tell XP to redetect the hardware (this does require going thru the setup process), and it will redetect, reconfigure, and load the appropriate drivers or ask for them.
formatting not required
you're at your "full" potential.
the only reason to start from scratch is if you don't know how to properly remove remnants of apps/drivers left over from removed hardware/software.
as for your cpu example, you simply tell XP to redetect the hardware (this does require going thru the setup process), and it will redetect, reconfigure, and load the appropriate drivers or ask for them.
formatting not required