I have XP Home 32 bit and I bought the Windows 8 Pro Upgrade disks from Newegg. Installing Windows 8 64 bit went fine but I can't activate the new OS using my XP activation key. I thought something might be wrong with the key so I reinstalled XP and it activated just fine. What's the proper procedure? I want to do a "Custom" installation to format my drive. Thank you for any help.