New versions of Windows never run on machines set up for the old version unless they've already been beefed up for gaming or CAD/CAM or other resource-intensive uses.
Resellers, Microsoft and hardware makers (and many CIOs, too, actually) were looking forward to Windows 7 actually forcing companies to buy more powerful PCs to run it.
That's a leap of two operating systems, not one, and the expectation that it would spark a buying spree was based on the assumption that companies that cut back their IT spending in 2008 and 2009 by delaying new PC purchases would replace the most aged machines with versions that would run Windows 7.
It worked, to a large extent. Sales of PCs did bounce up a bit after the debut of Windows 7 in October, 2009. Microsoft's jump of 51 percent in net income was only partly due to sales of Windows 7. Office 2010 and Xbox 360 sales helped, too.
Windows 8 is the first version of Windows expressly designed to run on tablets, which had been expected to erode sales of PCs by attracting users looking more for convenience than power.
Sales of laptops and PCs have been bouncing back recently, though, indicating the tablet frenzy that was going to replace every PC with a handheld may actually take up just a slice of the overall market – possibly focused as much on e-readers and streaming media as traditional PC-bound applications.
That's good news for Microsoft and its PC-centric products and resellers. It's bad news for anyone expecting to run Windows 8 on their existing hardware.
As the ship date for Windows 8 gets closer, Microsoft will have a lot of opportunities to make save-or-drop decisions on features that will make a big difference in how well the OS runs on machines that are two or three years old.
They may still be good machines, but they'll be underpowered compared to newer versions; if Microsoft focuses relentlessly on the tablet market, the version of Win8 that ships might work well enough on older machines.
If, it shoves off responsibility for developing a tablet UI to a subset of developers and lets the rest of the Windows group focus on the main OS, forget it.