Question : Re-install an XP-Home "Upgrade" system (activation and WGA issues)?

A friend wanted to start fresh, and completely re-install his copy of XP-Home. He also bought a new hard drive for the purpose.

His install was originally a WinME install that he upgraded to XP-Home (via a legit end-user XP-Home CD that he purchased).

How can he re-install that OS and successfully activate windows and pass the Windows Genuine Advantage validation for update.microsoft.com ?

Since he doesn't have a Full Installation version, he couldn't use his xp-home CD to install from scratch on the new drive. I got curious about how to do this, and tried the following:
1) Installed a fresh copy of XP-Home with a generated serial-number/cd-key using a full-install CD of mine.
2) Once installed (but before activation), I tried to change the key to my friend's legit key (which I found using MJ KeyFinder). But, it wouldn't accept the new key. I tried doing this from MJ KeyFinder, and also by starting the activation wizard, selecting the "Call Microsoft" option, and then "Update Product Key". Both methods told me that the key was not valid. I presume this is because the current full-install must recognize the key as an "upgrade" key.
3) So then I tried copying the WGA files (wga.dbl and wga.bak) from my friend's original xp-home install and putting them in the new install.
4) After I put those files in place, I went through product activation. It activated just fine, but not with my friend's legit key - the product key on the new install is still the generated one I used.
5) So the new install doesn't pass Windows Genuine Advantage validation when I go to update.microsoft.com. This is not a huge problem, but my friend has paid for the OS - he should have a legit install.

Any suggestions? Is there an accepted methodology for re-installing an xp-install that was initially an upgrade from a prior Windows version?

Answer : Re-install an XP-Home "Upgrade" system (activation and WGA issues)?

What you need is the XP Home CD, retail or upgrade.  You need a copy of windows 98 or ME.  Install the XP home CD, it will say that it did not find an operating system to upgrade and please insert a disc.  It is looking for the ME CD at that point, pop it in.  You are then told you can take it out and replace it with the XP home CD and then it will complete the Clean install.  I have a Windows 98  CD laying around just for such an occasion.