A trial version of a free anti-spyware tool to increase the security of the Windows operating system is being made available on a Microsoft web site.

The beta product was acquired last month with the purchase of Giant Company Software, Inc.
Spyware and viruses are intrusive programs that hinder computer performance and security.

A virus-removal tool is expected in the very near future.
It is anticipated that these products mark the entry of Microsoft into the computer security market.

Symantec and McAfee share prices declined following the announcement.