Users running copies of XP that Microsoft has already determined to rely on one of four pirated Windows license keys are now being asked to download the revamped tool. That will be gradually expanded over the "next several weeks and months," according to Microsoft, though users will continue to be able to de-select the update from being downloaded and installed.

The new version of WGA Notifications will also not incorporate a "kill switch" that cripples PCs that fail to prove that they are running genuine copies of Windows XP. That more aggressive feature, called Reduced Functionality Mode (RFM), is being in the upcoming Windows Vista OS.

The release also features a new installation wizard and will display validation results as soon as the tool has been installed. The software doesn't need to be rebooted after its installation, Microsoft said.

Microsoft plans to update the tool every 90 to 120 days, as a way to react to re-evaluation of the software and any changes in software piracy.