The Johannesburg, South Africa commercial bank plans to start upgrading to Windows Vista by March and have all of its 430 employees running the new OS by the end of 2007. "We have a very spoiled user base," said Dawie Olivier, Sasfin's project manager for information technology.

As part of Sasfin's normal three-year hardware refresh cycle, Olivier plans to bring in new PCs with Vista pre-installed. But he also plans to take the unusual step of retrofitting existing computers with more memory and faster video cards to handle Vista's beefed-up requirements. "We've decided it's not cost-effective for us to support multiple operating systems just because we're shy about cracking open a few PC cases," he said.

But Sasfin is the exception to what analysts predict will be the rule: Despite Microsoft's Thursday of Windows Vista, the operating system is expected to only slowly infiltrate businesses over the next two years.

By the end of 2007, less than 5 percent of installed PCs worldwide will sport some business-oriented version of Windows Vista, according to Gartner Inc. By comparison, 47 percent of PCs will likely be running Windows XP Professional, and nearly 10 percent of PCs will still be running Windows 2000 Professional, an operating system that will be seven years old by then.

The percentage of PCs running a business flavor of Windows Vista is expected to rise to 15 percent by the end of 2008. But that will still be dwarfed by the 40 percent of installed PCs still running Windows XP Pro.