Microsoft's mighty servers were overwhelmed as computer users worldwide rushed to download a free test version of a Windows 7 operating system being groomed to succeed Vista.
A virtual queue formed on the Internet in the hours on Friday before the planned release of Windows 7 "beta" software at noon local time in Microsoft's headquarters in Washington State.
"There was a line of people waiting online, so the noon release became an about-noon release," said a Microsoft spokesman showing off Microsoft's latest innovations at the Consumer Electronics Show in Las Vegas.
A flood of requests slowed Microsoft 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. Microsoft 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."
Windows 7 will streamline everyday tasks, cut boot-up times, extend battery life and make it simple to weave "smart" devices into home networks, according to Microsoft chief executive Steve Ballmer.
Ballmer said that the Windows software at the heart of Microsoft's empire is being "transformed" into a program that connects networks of computers, mobile telephones and applications hosted as online services.