While operating-system attacks are decreasing, attacks on applications are rising along with malware and unwanted software, according to the Microsoft Security Intelligence Report. Microsoft said 30 percent of the malware was Trojan-based, and China accounted for 50 percent of browser based attacks, while the U.S. was second at 23 percent.

The amount of malware and unwanted software removed from computers increased 43 percent in the first half of the year, according to the 150-page report, now in its fifth installment. Thirty percent of that malware was Trojan-based, usually in the form of a computer worm or virus disguised as another application that erases data, corrupts files, and reinstalls itself after being disabled.

Microsoft suggests consumers and businesses check for and apply software updates on a continuing basis, enable firewalls, and install antivirus and anti-spyware programs that add another layer of protection.

The software giant also suggests that consumers refrain from opening links and attachments in e-mails and instant messages -- even if they are from a trusted source -- without first considering the harm that opening may cause.