Since this article was originally posted, it has been updated to correct an inaccuracy in the fourth paragraph.Microsoft warned Friday that customers face security risks if they use some of its aging operating systems after it ends support for them next month.The systems affected are Windows 98, Windows 98 Second Edition and Windows Millennium Edition. Support will end on July 11, the next date for Microsoft\u2019s monthly security patches and software updates.Security updates will also end, according to a posting on the Microsoft Security Response Center.Microsoft said it wasn\u2019t feasible to make extensive changes to eliminate a security vulnerability since the underlying architecture of Windows Explorer for older versions of Windows is much less robust, wrote Christopher Budd, a program manager with Microsoft\u2019s security response center. "Due to these fundamental differences, these changes would require re-engineering a significant amount of a critical core component of the operating system," Budd said.As a result, applications may not run on the updated system, he said.Microsoft advised those still using the operating systems put them behind a perimeter firewall that filters traffic on TCP port 139, which will block attempts to exploit the problem, Budd said. Further, support for Windows XP Service Pack 1 will end on Oct. 10. \u2014 Jeremy Kirk, IDG News Service (London Bureau)Related Links:\n\nMicrosoft\u2019s Windows Vista Beta (Not) Publicly Available\n\nMicrosoft Unveils New Security Services\n\nA Win for Microsoft in Massachusetts?This article is posted on our Microsoft Informer page. For more news on the Redmond, Wash.-based powerhouse, keep checking in.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.