Microsoft Corp. said Monday it sold 20 million consumer copies of the new Windows Vista operating system worldwide in February, but analysts said the data shed little light on the program’s popularity during its first month on the market.

By comparison, Windows XP, Vista’s predecessor, sold 17 million copies in the two months following its 2001 launch, Microsoft said.

”It’s a stronger than expected start,” Bill Mannion, a director of product marketing for Windows, said in an interview.

But given that the personal computer market has nearly doubled since XP launched, Vista sales ”probably should be more,” said Michael Silver, vice president of research at Gartner, a technology research group.
But consider that more PCs are now in the home than there were when XP was launched. Also consider that all new PCs are being sold with Vista right from the first day if its launch. This wasn't the case when XP was launched, with many systems still selling with Me installed.