Actually I found in any NT platform, why not just go old school. Use the Computer Management feature? In there it gives you a list of any account (Under Local Users and Settings, then Users). You can click on the Guest user and then disable the account. That way no one can long in as a guest, there is no guest account, etc.

I've never used HomeXP though, I've only used XP Pro, and all the other NT platforms. As I've heard HomeXP is the same, just doesn't have certain features. Could someone let me know if this works? Thats what I do on all my machines after I install XP Pro.