"Microsoft is ending support for these products because they are outdated and these older operating systems can expose customers to security risks," a note on Microsoft's Web site reads. "We recommend that customers who are still running Windows 98 or Windows Me upgrade to a newer, more secure Microsoft operating system, such as Windows XP, as soon as possible."
Windows 98/SE/Me represent the end of the line for Microsoft's MS-DOS-based Windows versions. Current versions of Windows, such as Windows XP and the upcoming Windows Vista are based on a different code base that began with Windows NT. Windows NT and its successors are not based on MS-DOS, an operating system with roots dating back to CP/M in the late 1970's.
For Windows 98/SE/Me customers, the time to upgrade has come. Microsoft will stop providing paid incident support and, more important, any downloadable critical security patches, on July 11, 2006. Then, a year later, the company will cease providing self-help support online."
What can we expect the Expiry Date of Windows XP to be? According to their web site, "Mainstream support will end two years after the next version of this product is released. Extended support will end five years after mainstream support ends."
Windows Vista is expected to be launched in January 2007, so if your PC lasts another 3 years you're already in trouble.
Finally, Windows 98/Me Move Towards Retirement | Microsoft Notification | Microsoft Product Lifecycle policy