Make sure you
BACK UP!!! anything you want to keep, music, photo, FBI watch list, CTU database...
All you need to do is to boot from your Windows Home CD, it will guide you through the entire freash installation, format your hd, etc. As far as the Windows Pro, I say forget about it, since you are using a legit Windows Home. After that you will need to reinstall all programs include your internet setup.
B.