Security woes threaten innovation in the computer industry, but they also offer an opportunity to innovate that the industry should seize, Microsoft CEO Steve Ballmer said Monday."Today we're faced with another new and growing challenge to innovation. That is the need for the highest levels of security in a world that, frankly, is full of thieves, con artists, terrorists and hackers," Ballmer told an audience of Silicon Valley businesspeople at a luncheon organized by the Churchill Club in Santa Clara.Microsoft and the industry should not surrender but fight. "Our company and our industry have to hit on all cylinders to meet this new challenge," he said.Ballmer compared the threat of hackers and virus writers to that of bank robbers in the Old West. "In the Old West, the banks did not shut down because of the bank robbers. They improved the banks, they improved law enforcement and went after them," he said.The comments come just days after Microsoft warned of another serious vulnerability in its Windows software - one that is similar to the flaw exploited by the widespread MSBlaster worm a few weeks ago.Computers need a shield to protect against viruses, worms and hacker attacks, rather than products that deal with the problem after it has already reached the PC, Ballmer said. He described this "shield technology" as "perhaps the most important technical area" that Microsoft is focused on."We think that one of the best answers may be to stop the viruses at the front door, rather than having to deal with them at the backdoor, and that is a whole new front we think is a line of defense," he said. "We are absolutely committed to try to accomplish this notion of shielding."Ballmer said he understands customer's frustration and that Microsoft is working to ease customers' pain. However, at the same time Ballmer said computer users also have a responsibility."Too many users are not fully utilizing security technologies and not fully designing their networks for maximum security. There is a critical message that all of us in the industry need to convey to business customers and consumer customers," he said. Microsoft recently started a campaign that included full-page advertisements urging users to apply security patches.