Another worm has the attention of computer security experts.

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Anti-virus experts are monitoring the Sasser worm, which began spreading on the Internet over the weekend even though it may have a flaw.

They say the worm could cause unprotected systems to crash -- but doesn't appear to do any serious damage.

Steve Trilling at the Symantec Antivirus Research Center in California said the company received 2,900 reports about the virus from around the world by Monday morning.

He said computer users can avoid trouble by using anti-virus software and the right patches. Microsoft's MS04-011 security patch can stop the worm from spreading.

McAfee Security also offers a stand-alone tool to remove the malicious code.

Another research firm, eEye Digital Security, said that it was surprised the worm had spread at all because the code is poorly written.

Sasser is said to be spreading slowly. Some 25 to 50 companies reported infections on hundreds of machines, but the fast-spreading worms that have generated headlines have tended to infect more than 10 million machines.

Sasser spreads by automatically scanning for unprotected computers running Windows XP or Windows 2000, then downloads itself. It does not need to spread through e-mail.