"There's also a huge tail of XP in the market" he said, referring to users who declined to move to Vista. Tobul and other PC company executives stressed that Microsoft brought hardware makers into the testing process early on to avoid the well-publicized problems that hurt Vista.

PC shipments have progressively improved after a big collapse in the fourth quarter of last year, IDC's Daoud said. After three consecutive quarters of declining or flat shipments, IDC last week said global PC shipments grew by 2.3 percent year-over-year, to 78.1 million units, during the third quarter. IDC expects PC shipment growth of about 9 percent in 2010.

Revenue will also stabilize as PC shipments grow, IDC said. IDC estimates PC revenue will drop by 16 percent this year compared to 2008, but in 2010 it expects revenue to be flat or to grow 2 percent to $210 billion.

The surge in PC shipments will have a positive effect on semiconductor companies, with chip volumes rising as the market fills up with new Windows 7 PCs, said Avi Cohen, managing partner at Avian Securities. Chip makers such as Intel and AMD have ramped up their operations and added capacity in fabrication plants over the past two months.

The impact of Windows 7 on semiconductor companies is indirect, said Tony Massimini, chief of technology at Semico Research. Higher PC sales could improve the state of the semiconductor industry, in which a lot of fabs have been running on low capacity because of economic slowdown, he said. It could also improve sales of ancillary PC products such as printers and networking equipment, Massimini said.