Go to nvidia site and download the NF4 drivers, IIRC the realtek lan will be picked up by an XP SP2 install, if you are using OB sound visit Asus site for latest drivers.
If you are not using a raid array then SP2 will go straight on without any need of floppy/F6 routine.
If the system is already running, swapping the CPU does not require a re-install.