Microsoft is urging an estimated 70 million users of Windows 98 to upgrade as it ends support for the software.
From 11 July, Microsoft will no longer help users over the phone with any problems they have with the ageing operating system.
The firm will also stop providing security updates for Windows 98 from the same date.
Support for the software was originally due to end in 2003, but was extended following customer protests.
Products affected by closing down the support system include Windows 98, Windows 98 Second Edition, and Windows Me (Millennium Edition). Analyst firm IDC believes that more than 70 million users will be hit by the change.
The majority of these people are likely to be using the operating system at home, as by now most large businesses have phased out machines running the software. Many small firms are also believed to be users of the product.
Microsoft ended free support for this trio of products in late 2003 but continued to offer paid support and provide critical security updates. This too will now stop.
The change means that those still using Windows 98 and Me after 11 July could become more vulnerable to many security risks, as bug fixes for loopholes exploited by hackers will no longer become available.
In a statement Microsoft said it was "ending support for these products because they are outdated and these older operating systems can expose customers to security risks".
Mikko Hyponnen from Finnish security firm F-Secure said that it was still providing updates for Windows 98 users who run its anti-virus package.
"In fact, 98 users are not at that great a risk as people might think: most of the new malware we see simply won't run there," he said.
"Nevertheless, if you want to be safe with 98: don't go online. Or upgrade to something that is supported with security patches," he added.
From 11 July, Microsoft will no longer help users over the phone with any problems they have with the ageing operating system.
The firm will also stop providing security updates for Windows 98 from the same date.
Support for the software was originally due to end in 2003, but was extended following customer protests.
Products affected by closing down the support system include Windows 98, Windows 98 Second Edition, and Windows Me (Millennium Edition). Analyst firm IDC believes that more than 70 million users will be hit by the change.
The majority of these people are likely to be using the operating system at home, as by now most large businesses have phased out machines running the software. Many small firms are also believed to be users of the product.
Microsoft ended free support for this trio of products in late 2003 but continued to offer paid support and provide critical security updates. This too will now stop.
The change means that those still using Windows 98 and Me after 11 July could become more vulnerable to many security risks, as bug fixes for loopholes exploited by hackers will no longer become available.
In a statement Microsoft said it was "ending support for these products because they are outdated and these older operating systems can expose customers to security risks".
Mikko Hyponnen from Finnish security firm F-Secure said that it was still providing updates for Windows 98 users who run its anti-virus package.
"In fact, 98 users are not at that great a risk as people might think: most of the new malware we see simply won't run there," he said.
"Nevertheless, if you want to be safe with 98: don't go online. Or upgrade to something that is supported with security patches," he added.
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