Microsoft has begun reminding users of Windows 98, Windows 98 SE, and Windows Millennium that it will cut off all support for the aging operating systems in July.

"Microsoft is ending support for these products because they are outdated and these older operating systems can expose customers to security risks," the company said in a notice posted to its Web site. "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."

After July 11 -- the scheduled release date for that month's security bulletins -- Microsoft will no longer provide security updates for the OSes. Only online self-help support will be available, and that's guaranteed only through July 11, 2007.

On Tuesday, Microsoft provided three critical security patches for Windows 98 and Millennium, part of its lifecycle pledge to fix onerous bugs until all support is dropped.

Previously, Microsoft had extended the final support stage for Windows 98 and Millennium from January 2004 to June 30, 2006. In January of this year, the Redmond, Wash. developer announced that it would move the end date to July 11 to account for one final security bulletin release.

No-charge and extended hotfix support for Millennium ended December 31, 2003, and for Windows 98, on June 30, 2003.

Although Windows 98 may be found on numerous aged consumer machines, it's little-used in corporations. In a 2005 survey, for instance, Canadian asset-tracking firm AssetMetrix said that Windows 98 was running only about 5 percent of enterprise PCs.