Microsoft Ices Windows XP SP1

As of Wednesday, Microsoft will no longer support Windows XP SP1 and SP1a with security updates, although the day before it issued patches for 10 vulnerabilities affecting the operating system, 2 of which were judged "critical."

Months ago, Microsoft began warning XP SP1/SP1a users that support would end Oct. 10, and urged them to update to Windows XP SP2. As a parting gift, however, Microsoft released 10 patches for XP SP1/SP1a that included 2 pegged critical, 3 as "important," 2 "moderate," and 3 as "low."

Under Microsoft's current lifecycle policy, it promises to support Service Packs with security updates for 12-24 months after the release of a succeeding SP. Windows XP as a whole will age out of support only after two years have passed from the time Windows Vista is officially released.

Windows XP SP2, the free-of-charge update first issued in 2004, can be downloaded from the Microsoft Web site.