Windows Live OneCare Safety Scanner offered a free online scanning and protection from threats.

The "Full Service Scan" looks for common PC health issues such as viruses, temporary files, and open network ports.

[1] The service also provides a virus database, information about online threats, and general computer security documentation and tools.

It does not run periodic scans of the system, and does not provide features to prevent viruses from infecting the computer at the time, or thereafter.

Many users who have posted on the Product Feedback forum report script errors relating to Internet Explorer 7 (besides IE being the only browser supported by this service).