The only thing I don't like about that power supply is it blows air in onto the CPU, it doesn't exhaust air out. Look at this for an alternate:
You will need to buy a new copy of XP, but you won't have to wipe the drive - just do a repair reinstall. Get an OEM copy with your hardware purchase, it only has to match what you have now - Home or Pro. Use the new CD key and it will activate online.