What do you mean?
software? - drivers
only specific software drivers will work with the ethernet, video, audio hardware.
you can get these from the manufacturers website.
if you have ethernet, audio, video cards then these can be simply replaced but you will need to make sure you have the correct type of card as some graphics cards use PCI-e and AGP ports (See motherboard manual)
if your LAN, audio and sound are onboard (the motherboard) then these cannot be replaced without replacing the motherboard. However, you can add another LAN, audio and sound card to use these alternatively.