A 17-year veteran of Windows development, Nash said, "this is not a new problem." He is confident that for most users, the "short-term pain of transitioning from Version X will be outweighed by the duration of the benefit after you learn Version X+1."

Nash declined to comment specifically on a report that Microsoft plans to let to customers who buy Vista PCs after July 1.

Microsoft offered a for five months around the time of Vista's release.

"You can look at what historically our behavior has been," he said.

As for the Windows 7 beta, Nash said users can install an upgrade on top of Windows Vista, or do a clean install in an empty hard drive partition or in a virtual machine. They can even install Windows 7 in a VM on a Mac, he said.