Microsoft has updated software that verifies whether a copy of Windows is genuine in its Windows XP Professional edition, making it similar to the notification in Windows Vista and thus more persistently visible to users.

In a blog posting attributed to Alex Kochis, a Microsoft director of product marketing and management, the company said it made the changes to the Windows Genuine Notification (WGA) alerts for XP Pro because it is "the product edition that is most often stolen."

Now when a version of Windows XP Pro is found to be pirated or counterfeit, the next time a user logs on to the system, the desktop screen background will be black, replacing whatever custom desktop may have been set by the user. This will reappear every 60 minutes, even if a user resets the screen's background. Previously, this was not a part of the WGA notification for Windows XP Pro.

Another new feature of the alert system is to put the PC into "persistent desktop notification" mode, with a banner at the bottom of the screen informing the user that the copy of Windows is not genuine. The notification is translucent and users can interact with any objects underneath it; however, it will continue to appear on the screen until a user installs a genuine copy of Windows.

Microsoft said the update to WGA also simplifies the installation of the alert system on Windows XP Pro. In addition, the company has improved its ability to detect non-genuine copies of Windows.

Users have had mixed reactions to the WGA program, which Microsoft launched two years ago as part of an aggressive program to eliminate counterfeit and pirated versions of Windows. While some think it's a good way for Microsoft to prevent use of non-genuine Windows software, others found the program irksome and an intrusion, particularly when it would peg systems they knew to be genuine as pirated or counterfeit.

The program even at one point was thought to be acting like spyware by sending information from people's computers back to Microsoft. However, Microsoft said it only provides information about whether the copy of Windows is genuine, not any other information about the user or the PC.

Microsoft first distributed WGA only to users of Microsoft's download services who wanted to install add-on software, excluding security releases, for Windows XP. Eventually, it became an automatic part of Microsoft's update services and then was built directly into Windows Vista as the company developed that OS.