Microsoft has ended support for the Windows 95 and Windows NT 3.5x operating systems as of 31 December 2002.
The software giant ceased offline help for the operating systems over a year ago, but had continued to offer a limited online service.
Now that this has ended no more patches specifically aimed at flaws in these operating systems will be developed, and users will be unable to get advice or help from Microsoft.
Although ending support for the operating systems is likely to affect only a few people with older or secondhand PCs, support for three other major operating systems is due to enter the extended stage, where only general online help is offered, later this year.
Offline support for Windows 98, Windows 98 SE and Windows NT4 will cease in June this year, but an online service will be maintained until the end of June 2004.
The extended support phase for Windows Millennium is due to end in December 2004, but online support will continue for a further year.
And Windows XP professional will be supported until December 2008, but help for the home edition finishes a year earlier, in December 2007.
Geoengineering on the sea floor near glaciers would form a new ice shelf to prevent melting
Alterations in capillary blood flow can be caused by body position change
Curiosity rover is in 'normal mode' but not transmitting scientific data back to base
NatWest outage comes a day after Barclays' IT systems shut out customers and staff