Microsoft Corporation is close to releasing a major update for its Windows operating system, aiming to plug holes that have led to massive security problems for computer users everywhere. Microsoft senior product manager Matt Pilla says the company is expected to release the Windows XP Service Pack Two "in the coming days." Microsoft had delayed the release to improve compatibility between the new security functions and other applications. Among the changes, Service Pack Two automatically turns on a firewall to better guard against attempts to infiltrate personal computers. The update also fortifies protections on the Internet Explorer browser and offers tougher policing against e-mail-borne attacks. And it provides a user with much more information about what programs are trying to contact the computer, and gives the user more chances to accept or decline.