SAN FRANCISCO: The computer world's mischief makers struck this week with the first in what is expected to be a wave of viruses set to go off Jan 1, computer experts said on Friday.

A virus was discovered in computer systems of a number of companies, set to go off at New Year's and erase data from users' hard drives, security experts reported.

"This is the first Y2K virus we've seen that has really affected a number of people," said Sal Viveros, of Network Associates Inc, the largest computer security firm in the world.

Anti-virus firm Symantec Corp director of research Vincent Weafer said, "This is the kickoff for the Y2K -- which is going to be like the Super Bowl for virus writers."

The new virus, called W32/Mypics.worm, is set to disable computers as people try to start them up Jan 1. The virus writer apparently is hoping to mislead users into thinking they've been hit by the much-publicised Y2K Bug.

The virus is sent by e-mail with no subject line to a target user. Inside the e-mail is a message saying "Here's some pictures for you!" Clicking on the picture launches the damaging virus, or worm, a kind of virus that does damage but doesn't continue to propagate itself inside the host computer.

Like the earlier Melissa "worm," the new infection uses the target computer's Microsoft Outlook mailing list to send itself to 50 people via e-mail.

It can be detected ahead of the Jan 1 "payload date" through use of an anti-virus software, or by noting a suspicious switch in the default page of the user's Web browser.

Computer security firm Symantech, the company that first sounded the alarm about the Y2K bug, said it has found five different Y2K viruses in recent days, but none reaching the level of the W32/Mypics.worm, which it classed as a "medium to high-risk virus."

Simon Perry, Computer Associate International Inc's eTrust Business Manager said, "As the year 2000 quickly approaches, we are starting to see an increased frequency of dangerous viruses."

The year has already been marked by a wave of destructive infections, including the CIH, or Chernobyl Virus, which wiped out data on thousands of hard disk drives, and Melissa, which was one of the most widespread infections ever, though not as damaging to individual computers.

A concerted effort to sound the alarm by computer protection services has tended to dampen the spread of the viruses, though some see their alarms as self-serving, since most recommend a dose of their medicine, anti-virus software, as the cure.

"Once a virus is in the wild, and it's on everyone's detection lists, it tends to chill a bit. But that doesn't mean it's not still a threat," said David Perry, security firm Trend Micro Inc's pubic information director.

The most basic advice the security experts give is to avoid opening unsolicited e-mail. "Don't take candy from strangers," said Perry, "and don't open suspicious e-mail on your computer."--Reuters