Microsoft CEO Steve Ballmer says the task of trying to stay one step ahead of virus writers and hackers is <A HREF="http://news.zdnet.com/2100-1009_22-5394177.html?tag=zdnn.alert">a never-ending battle.</A> Speaking at a gathering of U.K. press, Ballmer said Microsoft's "trustworthy computing" effort is far more than just a one-off initiative.