All but conceding that its Windows Vista was a flop, Microsoft accelerated its effort to get its next-generation Windows 7 operating system out the door. Earlier this month, after hedging whether the software would debut late this year or in 2010, the company put a stake in the ground and said Windows 7 would begin shipping with PCs on Oct. 22.

And not a moment too soon. Microsoft has been losing market share as customers shunned Vista and turned to Linux and Apple's Macintosh computers as alternatives. But Windows 7 will be fighting a sales headwind as it's launched in the midst of a deep economic downturn.