" " CNN) -- Computer experts on Wednesday watched for an April Fools' Day computer worm to damage millions of infected computers.
However, fears that the worm, called Conficker.c, would cause chaos with Windows-based machines worldwide appear to be unfounded.
There have been no reports of problems so far.
As many as 10 million PCs are thought to be infected with the worm. In theory, that gives an unknown master computer control of these infected "zombies," allowing the master to push a malicious computer program onto the machines.
So far, that appears not to have happened, despite the fact that a bit of code in the worm had set it to launch automatically on April 1, computer experts said. iReport.com: What do you think of the April Fools' Day worm?
On a technology blog, The Washington Post mocked the hype about Conficker with an April Fools' Day post.
"Londoners woke up to find the iconic clock tower Big Ben stopped at precisely one minute till midnight," Brian Krebs wrote. "The British tabloids blared that the giant timepiece had been felled by the Conficker worm."
The post ends with this statement: "In case you haven't guessed it yet, APRIL FOOLS!!!"
A CNN technology expert says computer users do not need to panic.
"As long as you've patched or at least brought your antivirus software up to speed, you should be fine," said Chris Pirillo, a tech expert for CNN.com.
And there are plenty of anti-virus software packages available.
"I believe just about everybody out there," Pirillo said, "has a removal tool."
Still, the worm could cause problems, he said.
Unlike viruses, worms self-propagate, spreading by networks. "Once it's out there, it's very difficult to stop," Pirillo said.
He predicted that "the worst possible outcome" would be that some computers would run "suboptimally," as network traffic becomes clogged.
And its ability to do that is cleverly designed: Conficker.c has a feature that disables the Windows update program in the Microsoft product, keeping Windows from becoming patched, Pirillo said. It also disables the auto-update capabilities of many anti-virus software programs.
Pirillo said it may be a week or more before the true impact of the worm is known, but he predicted it will have one.
"It's going to be very annoying to say the least," he said. "It's going to impact network traffic.""