In just under a month, on July 11, the last vestiges of Microsoft's support for Windows 98 and Windows Millennium Edition (ME) will vanish. That includes support for Internet Explorer 6.

No more updates, no new versions, no security patches, nothing. When the next internet worm comes along, Microsoft will not be riding to the rescue for users of those OSes.

In fact, there has already been a foreshadowing of this – a recent security bug affecting all versions of Windows was deemed not feasible to fix on the 98 and ME line of operating systems, due to the limitations of the internal structure of the code.

And so even now, a fully patched installation of Windows 98 connected to the Internet without a firewall can be cracked remotely and completely controlled by an attacker. And Microsoft has no plans to do anything about it.

Fair enough. After all, you can't expect them to continue to support obsolete operating systems indefinitely. And they have already postponed the cut-off date once, from way back in early 2004. Of course, this may have had something to do with Windows 98's 27 per cent share of the worldwide OS market at the time. It doesn't do to abandon a quarter of your customers.

These days, Microsoft management may find the figures more palatable. Windows XP rules the roost, and 98 has only a 2 per cent or 3 per cent market share. (ME has almost no users; it was pretty much a flop from the outset.) But 2.5 per cent of the estimated internet population of 1 billion people is still 25 million machines.

So who are those 2.5 per cent? Windows 98 is still used on older computers, which came with it, or on refurbished machines that don't have the power for something newer.

And people are upgrading less often these days; you don't need the latest Pentium IV to surf the web, no matter how many dancing Intel engineers in clean room suits or blue-painted mute people try and tell you otherwise. (Plink, dum dum dum dum.)

Furthermore, it doesn't take all that many vulnerable hosts to cause difficulties. Back in January 2003, the SQL slammer worm, which exploited a flaw in Microsoft's SQL database engine, brought the internet to its knees for 24 hours and knocked entire countries off the map. How many infected machines? About 75,000.

This event – the end of life for Windows 98 - is really a first in the internet age. The last time this happened to a popular OS was back in 2001, for Windows 95. Five years ago, the Internet was a very different place. There weren't nearly as many worms, viruses and trojans floating around. And it was far easier to upgrade – the required specifications for Windows 98 were not all that much greater than 95.

So no-one really knows what's going to happen post-7/11. But one thing's for certain; as time goes on and more vulnerabilities are discovered, defenceless users of 98 and ME are going to be at greater and greater risk.

So what can Windows 98 users do? Microsoft's advice is unequivocal – upgrade. I'd agree - join the 21st century and get a better operating system. They'd recommend Windows XP; I'd recommend the newly-released Ubuntu Linux 6.06, which is easier to install, easier to use, more secure, and comes with thousands of pounds worth of free software. (Can you still find your Office installation disks? Didn't think so.)

If you must stick with Windows 98, at least install a firewall and get Firefox. But don't say I didn't warn you.

Gervase Markham works for the Mozilla Foundation, a non-profit organisation dedicated to promoting choice and innovation on the internet. His blog is Hacking for Christ.

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