Research firm IDC expects to see few Windows 8 upgrades on desktops and laptops, and it even predicts that users of conventional PCs won't show much interest in Microsoft's upcoming operating system.

Microsoft is facing a tough sell with the new operating system, IDC said, because it's trying to span two worlds by offering one platform for tablets and conventional PCs.

"Windows 8 will be largely irrelevant to the users of traditional PCs," said IDC. "We expect effectively no upgrade activity from Windows 7 to Windows 8 in that form factor."

Explaining the dour forecast, IDC analyst Al Gillen said, "Customers will be asking, What value does Windows 8 bring to my desktops and laptops?' And the only real value I can see is it provides access to the Windows app store."

Microsoft first confirmed in August that Windows 8 will feature access to a store; the store will open when the Windows 8 beta ships.

Gillen said that application compatibility issues, and the recent flurry of enterprise adoptions of Windows 7, will also hamper Windows 8 acceptance on PCs.

Gartner analyst Michael Silver agrees that Windows 8 will be a nonstarter in most enterprises; he has been quoted several times as saying "migration fatigue" is the biggest culprit. "After all the work on Windows 7 deployment, organizations will think twice about deploying [Windows 8]," Silver said in September. "They're looking for a little respite."

Windows 7 has indeed been aggressively adopted. The most recent figures from Microsoft show that the company had sold 450 million Windows 7 licenses as of September 2011, up from 240 million in October 2010.

Gillen was more optimistic about Windows 8 on tablets, but he said adoption depends on Microsoft's ability to convince developers to create new apps or rework existing Windows software for 8's Metro interface.