With PC users clamoring for Microsoft to continue to support Windows XP, Microsoft CEO Steve Ballmer's comments regarding Vista being "a work in progress" doesn't seem to help the company in its quest to instill confidence in the OS and get more businesses and consumers to upgrade - but at least he's telling it how it is.

At the Most Valuable Professionals conference in Seattle, Ballmer said he is well aware of the problems caused by the wide time gap between the launch of XP and Vista, reiterating that Microsoft won't again take five years to come out with a new operating system.

Even though he said a lot of customers are now using Vista, he went on to cite the need for further improvements in system performance, compatibility and battery life, and appeared to be open to a discussion about how long XP should be available. Ballmer spoke about a few other key areas that the company will focus on in the near future including virtualization, search, and hosted services.