okay, Im in serious hurt here. my restore disc no longer works on this machine. I have an hp pavillion with XP Home edition on it. I really need to reformat and rebuild the machine but I don't know what options I have here. I tried another XP Home disc from a friend and used my license key off of the sticker on the machine but it said it was not a valid key. are there different discs for different type of license and which one will I need for this machine so I can use the license key that I have.