Thanks for your comments, but now I see why I was confused. I purchased from COSTCO a box with two DVD disks in it; one for 32 bit and one for 64 bit. The box clearly says "Upgrade 3 PCs to Windows 7 Home Premium..." on it. It's an orange colored box called the Family Pack 3x, Upgrade 3 PCs for a SPECIAL price. So, up until your notes I assumed that by "upgrade" it meant I had to keep the original XP so the prior license would be recognized on the HDD. Ahhah, now I see in tiny font on one section of the box a notation that says "if you're upgrading from XP you will need to start with a clean install and then re-install all the apps...." This won't be a problem for me but I'm so sorry I didn't see that notation earlier. My other upgrades were from Vista, which did NOT require a clean install.
Thanks guys. I'll try it out and if it works on a clean install and I get the SP1 too, I'll mark this as closed.