During the first week after Windows Vista's launch, the product's unit shipments and revenue were lower (58.9 percent and 32.1 percent, respectively) than unit shipments and revenue for Windows XP during its launch week in 2001, according to Chris Swenson of the NPD Group. But the price of the high-end Vista Ultimate version might help make up for the lackluster start.

Swenson said that during the week in which Vista launched, the product's average selling price increased 65.5 percent (to $207.13) compared with Windows OS sales during the same period in 2006. Furthermore, Vista Ultimate accounted for at least 30 percent of the unit shipments in the retail channel. These figures led Swenson to conclude that "although total dollars were down compared with XP, the preliminary data shows that Microsoft's gamble on a new high-end Vista stock keeping unit (SKU) will help keep dollar volumes from declining as rapidly as unit volumes in the near term."

Vista sales were slower than expected during its launch week, but PC sales during the same week were up 67 percent compared with Windows OS sales during the same period in 2006, according to the NPD Group's Steve Baker. Of course, some of those PC purchases were probably delayed to coincide with Vista's availability on new hardware, but NPD sees a 67 percent increase in PC sales as representing "a fair amount of growth." Swenson said, "This preliminary data suggests that consumers are getting the message that they need a more robust system to take advantage of some of the new features in Vista, and thus a relatively smaller number are opting to upgrade older machines with the new OS themselves."

However, the increases in average selling price and PC sales didn't stop the decline in Microsoft's stock value. The stock decreased by 2.2 percent to a share price of $28.81 in response to Steve Ballmer's statement that revenue forecasts for Vista had been "overly aggressive."