Microsoft is to stop supporting Windows 98, 98SE and ME from 11 July.

After this date all public and technical support will be halted, and Microsoft also will stop security updates for these OSes, the company said. However, online self-help support will be available for the OSes on Microsoft's support website until at least July 11, 2007.

Microsoft said that it considers that these "outdated" OSes pose security risks to customers, and recommended customers still running these OSes upgrade to newer versions of Windows, such as Windows XP, as soon as possible.

Microsoft originally planned to end support for Windows 98 and ME in January 2004, but extended that to 30 June 2006, before announcing that final support would come on 11 July to allow for some last security patches.

Windows 98 and ME are less likely to be found in businesses than they are on home machines. According to a December 2005 Jupiter Research survey of nearly 2,300 PC customers, 16 percent were running Windows 98 or 98 SE in their homes, and 6 percent were running Windows ME.

Last month, Microsoft pushed back the release of Vista, until January 2007. Jupiter Media Analyst Joe Wilcox said that means customers still running Windows 98 or ME that must upgrade by July most likely will move to Windows XP, and forego upgrading to Vista upon its release in January. This poses a concern for Microsoft, which "still is not getting people to upgrade as quickly as they would like," he said.

Since Microsoft originally expected Vista would be released a lot sooner than it will be, it's possible the company thought it would be available when it decided to end support for 98, 98 SE and ME in July, Wilcox added.