What you would normally do is to activate the product hoping you could log-on back to the desktop. Unfortunately in most cases, the activation will not work. And in some other cases, when you activate the product, it would tell you that it is already activated but does the same anoying thing after a restart.

Here’s the fix that I’ve tested in quite a few Windows XP system. This works on either Windows XP Home or Professional. Just follow the steps in order:

1. Start your computer in safe mode (use plain safe mode).
2. Login using an administrator user account. If you could login to the hidden Administrator account, then use that.
3. Go to Windows Start menu and open RUN. Or you can press on your keyboard the Windows key and letter R.
4. Type CMD in the run textbox and click on OK. This will open the command prompt window.
5. Type these commands and press enter. Then click OK on each prompts :
   regsvr32 regwizc.dll
   regsvr32 licdll.dll
6. Type this last command (type exactly as what you see here):
   rundll32.exe syssetup,SetupOobeBnk
7. Wait for a couple of minutes because the last command will not show anything on the screen. However, it will reset the licensing components in the background.

You may now restart your computer and you can log-on back to your normal Windows desktop screen.