Analysts say Microsoft's new Windows XP operating system, to be launched this week, will be better able to fend off the hackers and viruses that have successfully breached previous versions of Windows.

XP, due to be available in retail stores Thursday, offers functions designed to fend off intruders and viruses, including a built-in firewall, software that blocks unauthorized access to a standalone computer or computers on a corporate network.

The Internet Connection Firewall will enable people with high-speed cable or DSL connections, which are more susceptible to hacking because of their always-on Internet connections, to be "invisible" on the Web, said Mark Croft, lead product manager for Windows XP.

John Pescatore, of market research firm Gartner, said the firewall offers "rudimentary blocking," so corporate users will probably still want to use a separate firewall product.

"It might be good enough for the typical home user," he said Monday, which could put a dent in consumer firewall sales for other companies.

In an attempt to keep viruses at bay--a problem that has plagued Microsoft's omnipresent software--the company also has included in XP a new software-restriction policy.

The feature lets network administrators block "executable" code that could automatically delete files or do other nasty things without computer users knowing it.

Meanwhile, McAfee has optimized its VirusScan Online automatic antivirus-software update service for Windows XP. Microsoft has included built-in support that will provide better protection for wireless connections, Croft said.

The fundamental architecture of the operating system has also been "hardened," or made more secure, according to Croft and analysts.

For instance, XP relies on fundamental Windows NT code for instructions, making it more difficult to hack into machines, said Rob Enderle of Giga Information Group.

The new operating system also uses the NT file system, allowing people to set user IDs and access controls on different files within a computer. This will allow parents to prevent their children from accessing sensitive information on the hard drive, said Russ Cooper, a researcher at TruSecure and editor of the NTBugtraq mailing list.

A new "file scrubber" feature, which erases deleted files so they are nearly impossible to recover, will likely be applauded by privacy advocates.

At the same time, several features designed to improve the way XP systems are managed could give malicious hackers an inroad to the systems, the experts said.

XP automatically sends information between the PC and Microsoft about product registration, new bugs and software updates. The operating system also has a new remote control feature to allow a help desk or administrator to take control over a desktop from a different computer.

"Really, it's the only net negative of the new features," said Pescatore. "I think they've put in place a lot of processes that should result in XP and (versions) beyond being a lot more security-stable than previously."

Overall, XP is an incremental jump in security from Windows 2000, Pescatore said, adding that Windows 2000 was a huge advance in security over Windows 95.

XP is Microsoft's latest step toward evolving Windows away from the standalone PC to a Web services oriented world. Under the .Net initiative, applications and information will be stored on servers connected to the Internet, accessible from any device from any location.

Although XP itself has features that will make it safer from security vulnerabilities and attacks, risks are magnified the more the desktop is linked to Web services and data are aggregated in one central location, experts said.

For example, .Net will store personal profiles, contacts, calendar, electronic-wallet data and other information people will want to access, using .Net's "My Services" technology, formerly called HailStorm.

"What makes it a problem is when My Services rolls out" in February, said Enderle. "That creates a single point of attack" for malicious hackers.