Microsoft has made a last-minute decision to extend support for Windows 98 and ME until 30 June 2006.

Support for 98 was due to end this Friday (16 January) and users given no more than a CD to help them "make the most of" the operating system. ME support was due to expire on 31 December this year.

But in a peculiar turnaround - only announced after press reports forced Microsoft's hand - the software giant has decided not to ditch the millions of users that still happily use one of Microsoft's most stable Windows incarnations.

Microsoft's official Windows 98 website still states that support will end on Friday and it is clear the giant was caught on the hop when details leaked. Presumably it was hoping to announce the extended support on Friday and pick up some favourable stories. It had certainly planned to update its support site with new details on Thursday.

As to why the company has left it so late in the day, the bland official explanation is "in order to provide a clear and consistent date for support conclusion for all of these older products" for 98 and ME and "bring it into compliance with the company’s current lifecycle policy for new products, which provides for support for seven years instead of the original four" for 98 SE.

The real reason is far more likely to be one of security. Microsoft is embarking on a massive anti-Linux drive and it has recognised that security is one of the biggest selling points that the open-source OS has over Windows. It is also promoting security problems with Linux in order to make a grass-is-greener argument.

Windows 98 in particular is still used by millions of customers and removing support would have left them at the mercy of worms and viruses. Not great PR. While Microsoft has always assumed people will simply upgrade to its latest OS, there is a huge risk that large numbers will simply shift to a new OS.

So until 30 June 2006, Microsoft will "continue to offer paid phone support and will continue to review any critical security issues and take appropriate steps". Which can only be a good thing. But the last-minute turnaround is intriguing and almost certainly an indication that Microsoft is as worried about Linux on the desktop as everyone wants it to be.

From Thursday, MS' support site will give a full rundown. See http://support.microsoft.com.