Software giant Microsoft's new operating system, Windows 7, will be available in the market by Christmas 2009, the company's chief executive officer Steve Ballmer said here on Wednesday.

"Our previous operating system Vista was popular ... rather much talked-about. But Windows 7 will be simple to use. The Windows 7 development is underway according to our plans," Ballmer said while delivering the keynote address at Microsoft's Tech.Ed India at the Hyderabad International Convention Centre.

Windows 7 would be more "reliable, secure and productive," the CEO pointed out. A Beta version of Windows 7 was currently available for users.

Emphasising the need for "more innovation and productivity", Ballmer said the next round of growth has to come from productivity and innovation.

"Global economy is in the process of re-setting. The good news about the current economic recession is that it happens only once in a lifetime.

And, the bad news is that the next generation will not learn from the current generation," Ballmer noted, referring to similar economic crises that hit the world largely way back in 1879 and 1929.

"We are, however, optimistic about the future," he said.