Microsoft isn't the first company to offer free anti-malware software. Some other security vendors make their products available to individual, non-commercial users at no charge.
Examples include AVG (though AVG Free does not protect against rootkits or web exploits), PC Tools (PC Tools AntiVirus Free and Spyware Doctor Starter Edition are separate products) and Avast.
Retail sales of Windows Live OneCare will end on 30 June 2009, but direct sales won't be phased out until Morro ships. Updates will continue as long as any customers have a current subscription to the service.
Microsoft's Forefront security products for enterprise customers will continue to be developed.
"Providing access to a trusted solution at no charge is the right thing to do to help protect our customers," said Barzdukas.
No doubt the cynical will suggest that if Windows was more secure in the first place, products such as Morro or Forefront wouldn't be needed.
Others will say that Windows' huge marketshare makes it a more lucrative target for malware writers, and that other platforms are not inherently more secure.