The dreaded Conficker Windows worm phoned home as ordered Wednesday — but so far hasn't launched a full-scale attack on the Internet.
Computer security experts breathed sighs of relief and satisfaction that their predictions that nothing would happen had proven true.
"One thing we're not seeing is any mass malicious activity," said Joris Evers, an analyst with McAfee. "The Internet today is working just as well as it was working yesterday."
The sneaky worm, which can jump between computers without human aid, has infected an infected 3 to 12 million PCs and servers since last fall.
Some heightened network activity was detected in Australia as the clock passed midnight there and infected machines tried to get new instructions from secret locations.
The worm can take control of unsuspecting PCs running Microsoft's Windows operating system. But its creators likely want to use their vast "botnet" to send spam or perform other cybercrimes, and not to bring down the Internet.
That's one reason analysts say the people behind the virus will probably wait to send any commands.
"Everyone who is fighting Conficker is on high alert," Evers said.
Security companies monitoring the worm have been largely successful at blocking infected machines from communicating with whoever programmed it.
Microsoft issued a software update, called a "patch," to protect PCs from vulnerability back in October. But not everyone applied the patch, and some versions of Conficker actually patch Windows themselves after they've made their way into PCs.
In one telltale sign of an infected machine, Conficker blocks Microsoft's site as well as those of most antivirus companies.
Computer owners can work around that obstacle by having someone else e-mail them a Conficker removal tool.
The Associated Press contributed to this report.