"Due to pent-up demand for PCs with Vista pre-installed, we anticipate a spike in PC sales during the March quarter, which could put downward pressure on Mac market share," Munster wrote in a note obtained by MacNN. "We also anticipate a general increase in computer sales, including Macs, as customers consider several options for their computer purchase." Munster expects that Mac market share will decline from 2.5 percent in December to 2.3 percent in March; however, he believes that Apple will gain share in 2007 despite the Vista-related refresh cycle. The analyst notes that Apple is taking advantage of the upgrade cycle -- what it calls the "Vista opportunity" by direct marketing to iPod users and well placed television campaign focused on the hassles of upgrading to Windows Vista. Around the time of the consumer Vista launch, Apple initiated several strategies to attract Vista customers, the firm noted. In an email to registered iPod owners with PCs, Apple asked customers: "Upgrading to Vista? Think Mac." Apple also launched national TV ad campaigns in the US as well as the UK and Japan criticizing Vista's difficult installation process and frustrating security features. "The company's retail stores will also be used in an effort to monetize the 'Vista opportunity' as store employees are mphasizing the fact that Macs run both Mac OS X and Windows," Munster wrote. Vista sales slow, pre-installed Vista PCs sell well The firm's survey of 50 Best Buy stores around the U.S. found that Vista sales have not met expectations, but that PC sales have increased since Vista's launch. Of the 50 stores Piper surveyed, 80 percent indicated that they have sold fewer copies of Vista than they had expected; however, more than 70 percent of the stores indicated that PC sales have increased since the Vista launch. Piper Jaffray has an 'outperform' rating on Apple stock with a target price of $124.