Windows 7, Microsoft’s new operating system (OS), which was recently released, will have minimal impact on PC sales, according to researcher Gartner.

“The OS is not the reason people upgrade their PCs,” says Mikako Kitagawa, principal analyst at Gartner. “On the consumer side, people upgrade their PCs if their current PC is old or if they want more PCs in their home or if the price is really good,” she says. “But people don’t buy simply because a new operating system is available.”

On the business side, Windows 7 won’t have an impact on sales to business until at least the second half of next year.

IT departments at companies usually test a new OS for about a year before rolling it out company-wide. Usually companies need to test a new OS to see how their applications run and if there are any glitches, says Kitagawa.

However, although Windows 7 won’t immediately impact PC sales, computer shipments will rise over the next year. In fact, shipments are already increasing

PC unit shipments increased 0.5% in the third quarter of 2009 compared to the third quarter of 2008. Shipments in the third quarter were 18% higher than the second quarter. In 2010, shipments will increase 12.6%, says Kitagawa.

PC shipments will rise as the economy recovers. Many companies have delayed buying new computers because of the downturn, but their current computers systems are getting old and need to be replaced.

However, while unit shipments have increased, PC revenue declined 20% in the third quarter and will be down 16% for the year, says Kitagawa. Many consumers are opting to buy low-priced netbooks, which cost less than full-featured notebooks and desktops. That is putting pressure PC OEMs to lower the cost of notebooks.