Twenty-one months after its initial release, what do we know about Windows Vista ? That home users hate it, businesses are uninstalling it and - according to Gartner - it's proof that the 23-year-old Windows line is "collapsing" under its own weight.

Meanwhile, predecessor Windows XP, which Microsoft stopped shipping to retailers and the major PC makers on 30 June, has belatedly become so beloved.

But all of the griping about Vista and instant nostalgia for XP covers up a dry, statistical reality: XP itself was slow to catch on with users - maybe even slower than Vista has been thus far. For instance, in September 2003, 23 months after its release, XP was running on only 6.6 percent of corporate PCs in the US and Canada, according to data compiled by AssetMetrix, an asset-tracking vendor that was later bought by Microsoft.

In comparison, Forrester Research reported that as of the end of June - 19 months after Vista's November 2006 debut for business users - the new operating system was running on 8.8 percent of enterprise PCs worldwide. Forrester analyst Thomas Mendel, who authored the report, wasn't impressed: he compared Vista to the ill-fated New Coke.

However, even Gartner, that prophet of Windows' doom, forecasts that Vista will be more popular at the end of this year than XP was at a similar juncture - with 28 percent of the PC operating system installed base worldwide, vs. 22 percent for XP at the end of 2003.

"The uptake of XP was slower than people remember today," said Michael Cherry, an analyst at Directions on Microsoft in Kirkland, Wash. He noted that many IT managers "labelled XP a consumer-only upgrade" at first.

Early opinions of Windows XP were remarkably similar to those that many users offer about Windows Vista today.

For instance, a Computerworld survey of 200 IT managers conducted in 2001, just before XP was released, found that 53 percent of the respondents didn't plan to upgrade their PCs, while another 25 percent were undecided. And in an informal poll of 25 users a year later, only four said they had started deploying XP.

"We have not moved to XP, and we have no plans to," one CIO said in 2002. "This is an upgrade that offers nothing to a business customer."

Another IT manager said that the cost of upgrading to XP was "very high" and that there wasn't "a lot of perceived value" in moving up.