Microsoft will soon offer free security programs.
One removes viruses from infected Windows computers, the other removes so-called spyware.
Microsoft says the anti-virus program isn't intended to replace the need for third-party anti-virus software. The Microsoft software doesn't prevent infections, but removes the virus after it has installed itself on the user's PC.
The new Microsoft program is a step toward plans by the company to sell full-blown antivirus software later this year.
Microsoft has been criticized for being too slow in protecting its software from malicious programs spread by computer viruses.
The new security programs will be available on the Microsoft Web site.