One of the problems with using virtual computers is that the hardware is virtual and somewhat easy to change, but the Windows registration is based on the hardware. Sometimes copying the WPA.DBL file can fix the problem.
I didn’t keep good notes on this, but I think the problem was caused the updating the Vmware tools in an image. After those changes, the activation screen displayed and I could not login. So, I copied the wpa.dbl file from an old copy of the Vmware Image and overwrote the file in the new image. After that, I never saw the activation screen again.
I tried this same approach when I attempted to migrate a Windows image to a VMWare image. It did not work that time, and I ran out of time to figure out why.
File Location: c:\windows\system32\wpa.dbl
Windows Tip of the Day: Avoid Re-Activate Windows XP After a Reinstallation
Windows Product Activation (WPA) for Windows XP
Windows Product Activation (WPA) on Windows XP