As part of the Windows Live services that Microsoft touted Tuesday, the Redmond, Wash.-based developer rolled out a beta version of a free Web service that scans for and removes viruses, removes unnecessary files from the hard drive, and schedules a disk defragmentation. Some users may be uneasy about using the service, however, since by default the virus scanner transmits information about the PC and its applications to Microsoft.

Windows Live Safety Center is a free, albeit advertising-supported site. It takes its cue from the also-in-beta OneCare subscription service, which Microsoft's pitching as a persistent security service that can counter developing threats. Safety Center, on the other hand, is an on-demand service only able to detect and delete threats that have already gotten a foothold on the PC.

"It’s like taking your PC in for a tune up and oil change at the service station," said Microsoft on the site.

Its tools include a virus scanner, disk defragger, file clean-up utility, and open port sniffer. All are ActiveX based, so running them requires Microsoft's own Internet Explorer. It works with Windows 2000, XP, and Server 2003 systems.

By default, the virus scanner reports back to Microsoft with details of the machine, including the operating system (its product ID, among other things), installed drivers, and installed applications. Microsoft said that the collected data would be used to "help us improve scanner features and make better recommendations." The user can choose to not transmit some of this data by clearing a check box in the scanner window.

"If you elect to share your results with us, all reported information is anonymous. No personal information is collected," Microsoft said.

The scanner transmits some information, including the results of the virus scan and its performance on the machine, to Microsoft automatically, no matter what choice the user makes.

Microsoft has set up a blog to take comments and criticisms of the new service.

Windows Live Safety Center can be found here.