Microsoft Corp. said Wednesday it will exploit a network of 25,000 post offices in Japan to provide a free CD-ROM version of the Windows XP Service Pack 2 with added security features, beginning Oct. 1.

The update will help computer users protect their machines from viruses and hackers, according to the U.S. computer software giant.

A spokesman for Japan Post, which runs the post office network, said the Microsoft plan constitutes a public service at a time when the Japanese government is promoting Internet security measures.

The Windows XP SP2 features the new Windows Security Center, which allows users to check whether the operating system is safe, as well as the Windows Firewall, which detects and guards against hacking, Microsoft said.

Beginning Thursday, the software will be available via free download from the Microsoft Web site. The CD-ROM version will also be provided at major consumer electronics stores, it said.