After a virus forced me to reformat my Windows XP, I've been having an issue reregistering it. Before, I had used my dad's laptop Product Key, since I didn't have the XP's, but this time it won't work!
Since I have access to the internet, I've been able to get onto the Internet Explorer when it asks me if I want to go to the Microsoft Activation Assistance Site. Once there, I can pretty much use my computer, since I can access "My Computer" in the URL box.
I've been to countless websites and used hundreds of different product codes but they all don't work.
I've even downloaded a program that'll tell you what your Product Key is - and even THAT won't work!

Please, I just want to get onto my desktop and have my computer running normally again. You have no idea how grateful I'll be if someone can help me fix this problem.

Oh, almost forgot -
The Windows XP Operating System is running on a Windows ME Computer-
We had an ME for about two years, but my brother got a Windows XP Installation CD from a friend, and so the label on the computer tells me the Product Key for the ME, not the XP...