Microsoft Stepping Up Anti-Virus Efforts

Microsoft Corp. Chief Executive Steve Ballmer said the company would make any necessary improvements in its software to try to thwart viruses and other attacks that recently have hobbled computers around the world.

"We are in many ways humbled by the developments of the last few weeks," Ballmer said in a speech at the Churchill Club, a Silicon Valley business networking group.

The Blaster, or LovSan, worm exploited a flaw in most versions of Microsoft's Windows operating system, infecting hundreds of thousands of PCs.

Besides trying to write more secure code, Microsoft is investing in "shield technology" to block viruses from reaching PCs, Ballmer said.