A new Windows XP "security update" from Microsoft is actually a tool that checks whether or not Windows XP is properly licensed on the computer.

"The Windows Genuine Advantage Notification tool notifies you if your copy of Windows is not genuine. If your system is found to be a non-genuine, the tool will help you obtain a licensed copy of Windows."

This 'tool' has been criticized for a number of reasons.

Microsoft is presenting this tool as a Critical Update but it has nothing to do with security. As Microsoft operating systems are so notoriously hard to keep secure, I recommend to my clients that they keep "Automatic Updates" turned on. This puts a lot of trust in Microsoft as they can install software at their own discretion. They would do well not to abuse this relationship by slipping in non-essential code.

Also, after initially checking to see if the XP licensing is valid, this tool purportedly continues to recheck each time the computer starts. This ties up system resources needlessly. I see this as a further way in which Microsoft's policies actually punish their paying customers.

"RemoveWGA enables you to remove the Microsoft Windows Genuine Advantage Notifications tool, which is calling home and connect to Microsoft servers every time you boot.”

RemoveWGA only remove the notification part, phoning home, and does not touch the Validation part. As the time I'm writing this, the Validation part is mandatory for some not critical downloads from Microsoft, but the Notification part is not mandatory at all, and you are able to install all of the security updates without installing this one. This may change in the future thought, I don't know what are the Microsoft plans."