Microsoft has stopped offering free downloads of Microsoft Security Essentials just a day after it launched Microsoft Security Essentials.

Microsoft said it has reached the number of participants it was looking for. The software maker further said it was looking for 75,000 downloads of the product, formerly code-named Morro.

Microsoft said on its Web site, "Thank you for your interest in joining the Microsft Security Essentials Beta. We are not accepting additional participants at this time. Please check back at a later date for possible additional availability."

Microsoft Security Essentials, free security product, hits the antivirus basics, including built-in and customizable scan options, a scheduler, automatic definition file updates, a real-time defense shield, and rootkit protection.

Microsoft Security Essentials is currently being beta tested in the U. S., Brazil and Israel, with 32- and 64-bit versions of the anti-malware application running on Windows XP, Windows Vista and Windows 7 in those markets.

Microsoft will discontinue its commercial Live OneCare product on June 30. But users have a replacement with Microsoft Security Essentials, and several early reviews say that the product is fast and efficient for those who can't afford or won't otherwise pay for security on their PCs.

According to the company Microsoft Security Essentials' Dynamic Signature Service identifies malicious files by questioning its Dynamic Signature Service, which updates signatures after being triggered by suspicious actions.

However, it is yet to be witnessed whether Microsoft Security Essentials will withstand the test of time.