Although many antivirus companies offer free software for personal use, Microsoft Security Essentials is the first offering that entrepreneurs can rightfully use on their home-business computers, TechRepublic reported.

This is great news for small business owners concerned about the security of their PCs from viruses and malware that can leave them vulnerable to identity theft and other attacks.

Microsoft reported on its Malware Protection center blog that the antivirus suite has been downloaded 1.5 million times in the first week of its release. Nearly half (44 percent) of the downloads have been on Windows 7-based PCs.

The security suite has already cleaned nearly 4 million viruses on 535,752 distinct machines, with many PCs being infected by multiple viruses, Microsoft said.

Microsoft Security Essentials has detected more than 60,000 Trojans on U.S. Windows computers. Trojans are pieces of malware that disguise themselves as harmless files.

When downloaded, Trojans can steal sensitive information like email passwords and bank account numbers.