A recent blog by Chester Wisnieski, entitled Windows 7 vulnerable to 8 out of 10 viruses, which has stirred some interest and discussion is going on Forum and Community websites. But all the claims are being made, not a valid vulnerability test.
Windows Team Blog says:
During a test SophosLabs conducted, they subjected Windows 7 to "10 unique [malware] samples that arrived in the SophosLabs feed." They utilized a clean install of Windows 7, using default settings (including the UAC defaults), but did not install any anti-virus software. The end result was 8 of the 10 malware samples successfully ran and the blog proclaims that "Windows 7 disappointed just like earlier versions of Windows." Chester’s final conclusion? "You still need to run anti-virus on Windows 7." Well, we agree: users of any computer, on any platform, should run anti-virus software, including those running Windows 7.
So there is no mean to count on such unofficial test and even a End-User knows his/her PC will be infected and gone down, if he/she run malicious program. Windows 7 is built upon the security platform of Window Vista, that has significant changes than earlier version of Windows including UAC, DEP, Kernel Patch Protection, Windows Defender and so on excluding AV program, that is essentials part of Security and Microsoft offers a free AV solution called Microsoft Security Essentials. A part from all these things, it is recommended to keep Windows updated. Therefore configuring Windows Update to download and install updates automatically you will help ensure that you have the highest level of protection against malware and other vulnerabilities.