Microsoft has warned that one in every 14 programs you can download will be malware.
Writing in his bog, Volish SmartScreen program manager Jeb Haber said that feedback from Microsoft's Internet Exploder showed that one in every 14 programs downloaded turned out to be malicious code.
Haber said that social-engineering attacks, like tricking a user into running a malicious program, were more common than attacks on security vulnerabilities.
He said that Vole's "SmartScreen" technology has blocked more than 1.5 billion attempts to slip malware into computers since IE8 was released in 2009.
According to Haber, user-downloaded malware is a huge problem and is getting bigger.
IE9 checks the reputations of websites and their creators to let internet users know when they are dealing with unknown sites. Its theory is that people should be cautious about buying something online from a complete stranger.
The idea is reputation software helps protect users from newly released malware programs which pretend to be legitimate software.
However, generally, social engineering techniques appear to be successful and trick a large number of people into downloading bogus software.