Microsoft's Windows Genuine Advantage is being updated today, in what the company claims is response to customer feedback.
The original WGA was hugely unpopular, especially when it emerged the software was secretly "phoning home" - sending information about users' computers back to Redmond.
It also caused problems for some network managers faced with dozens of "false positives" - users told they were running fake software when in fact they were not. The original WGA found 22 per cent of systems scanned failed the test.
Microsoft has taken a page out of the Scottish legal system and added an extra verdict of "not proven" - WGA for XP will now label your software genuine, non-genuine, or not sure. Last time round some users found minor hardware changes like installing a new video card meant they had to re-activate their software through WGA.
The opt-in software is available for download from www.microsoft.com/genuine/.
It will then be rolled out in Automatic Updates over "the next several weeks or months". The software will be updated every 90 to 120 days.
Microsoft UK anti-piracy head Michala Alexander told us: "There's no denying WGA has had its challenges but we really think we've listened to customers. When a customer fails it now gives more information as to why. Some 33 million people have gone through WGA now in the UK alone. We've added a glossy wizard to make it easier for customers. If any IT manager does have problems, please get in touch and we'll try to help."