MICROSOFT'S mighty servers were overwhelmed today as computer users worldwide rushed to download a free test version of Windows 7.

A virtual queue formed online in the hours before the planned release of Windows 7 "beta" software at noon local time (7:00am AEDT) in Microsoft's Washington State headquarters.

"There was a line of people waiting online, so the noon release became an about-noon release," said a Microsoft spokesman showing off the company's latest innovations at the Consumer Electronics Show (CES) in Las Vegas.

Microsoft's download page is currently displaying a statement apologising for the delay.

"The volume has been phenomenal," the statement said.

"We’re in the process of adding more servers to handle the demand. We’re sorry for the delay and we’ll re-post the Beta as soon as we can ensure a quality download experience."

A flood of requests slowed Microsoft's industrial-strength computers, causing delays and disappointments.

The window for downloading the test-version of Windows 7 closes the last day of January, Microsoft said.

Learning curve

The software giant wants feedback from users to refine the new operating system, but doesn't plan to change or add features.

"We got ourselves in a little trouble with Windows Vista; it became a bag of mixed things and didn't really figure out what it was about," said Mike Ybarra, general manager of Windows products at Microsoft.

"There was a lot of feature creep. You had people saying 'Let's change this and that.' Windows 7 has been very disciplined."

Analyst Michael Cherry of private firm Directions On Microsoft says he is impressed with the way the software giant "kept its enthusiasm under control."

Microsoft improved the Vista operating system while making sure it is "backward compatible," essentially that it will work with older software.

Vista was such an advance over Windows XP that it clashed with software people already used and previous generation computers.

"Microsoft is making the kind of evolutionary changes they need without the revolutionary changes that break things," Mr Cherry said.

The company has been secretive about when a finished version of Windows 7 will be ready.

Mr Cherry believes the goal is to get it to market in time to be pre-installed on new computers sold during the prime US back-to-school and year-end holiday shopping seasons in 2009.