David Daoud ran into trouble when he started using Vista, the new version of Windows that Microsoft and PC makers have spent millions of dollars advertising since it came out six months ago.
He said it short-circuited key software programs he counts on: Quicken for balancing his checkbook, Lotus Notes e-mail and a networking program that connects his home to the office. His Sony camcorder also doesn't communicate with the PC properly.
"Basically they don't work," said Daoud, a computer industry analyst with market research firm IDC.
Such problems are part of the normal growing pains that come with every major upgrade to the Windows operating system.
To ease those pains, some consumers are seeking out machines equipped with the more compatible Windows XP. That's prompted some PC makers and retailers to give the older operating system more room in their product lines.
Hewlett-Packard and Dell recently started selling XP machines on their Web sites. Lenovo Group and Toshiba also offer similarly equipped machines.
Microsoft has done its best to get Vista off to a strong start, making it compatible with more than 2 million different types of hardware.
The effort seems to be paying off. The company late on Thursday reported quarterly revenue of $13.4 billion, up 13 percent from last year, citing help from strong Vista sales.
Microsoft says most people using Vista are pleased with it and that nearly all software and hardware is compatible.
Still, some companies have been slow to respond to Microsoft's call for upgrades. Consumers have taken note.
Craig Rabe, owner of the Computer Cafe, an independent computer store in Arlington, Mass., says he received so many complaints about Vista after it was launched in February that he stopped selling machines loaded with the software.
"People came back and said, 'Please, will you take this off and replace it with XP?'" he said.
Testing users' comfort level
The Massachusetts Institute of Technology is advising incoming freshmen to buy PCs loaded with Windows XP.
"XP is still fully functional. It's what people are familiar with," said Jon Hunt, who made the decision for MIT. But he expects MIT will soon start supporting Vista.
Among retailers, CompUSA says it has the widest selection of XP machines, something it plans to tout during the busy back-to-school sales season.
Circuit City Stores offers nine XP models on its Web site. Best Buy does not carry XP machines.
The Windows User Group says Vista is an "awesome" system and all of its employees use it. But the company, which provides technical advice on Windows and runs online communities, cautions that the switch can be uncomfortable.
"My father-in-law, my niece, my accountant--they all have computers running XP now. If they put Vista on top, not everything is going to work," said WUG vice president Joel Diamond.
Microsoft says it has put a lot of effort into working with other companies to solve any problems.
"There are some products that don't work with it," said Windows group product manager Justin Jed. "But ... the data shows louder than the anecdotes that people are having a great experience with Windows Vista."
He says 72 percent of users have a "favorable" view of Vista, 8 percent "unfavorable," with the rest neutral.
What's more, about 96 percent of all printers, keyboards, mice, scanners and other devices in use are compatible with Vista, as are about 2,000 software programs, including 49 of the current 50 best-selling retail titles, he says.
But while Adobe recently introduced a version of Photoshop professional that works with Vista, customers with the previous edition have to pay $199 for an upgrade.
Norton SystemWorks, a $70 security program, has yet to be made Vista compatible though the company says it is in the works. TiVo software for linking to PCs is also incompatible.
Microsoft declined to comment on specific problems.
"We are going after the ones that impact the most customers," Jed said. "Obviously you cannot be all things to all people."