Microsoft is starting to roll out a new version of its Windows Genuine Advantage (WGA) software for Windows XP Pro.
The new version of WGA will work much like the anti-piracy software implemented in Windows Vista. Your PC will not be immediately disabled if it fails the WGA check. Rather when you login you’ll see a black desktop background instead of your background of choice. You can change the background, but every 60 minutes it will reset itself to black.
There will also be a warning notice that you cannot make go away unless you enter a valid Windows license key.