Your personal computers have been updated and you're Y2K ready. All set to face the new millennium? Think again.

The Malaysian Computer Emergency Response Team (MyCERT) is warning computer users to be wary of viruses that attack on the eve of the new Millennium and on New Year's itself. What's more, the millenium viruses may have already infected your computers where they will lie dormant until Jan 1 when they will wreak havoc when the computer is powered.

"Update your anti-virus programme now before it is too late," said MyCERT project head Raja Azrina Raja Othman. Anti-virus companies have detected more than half a dozen of such viruses, all transmitted via e-mail, that may hit computers worldwide on Dec 31 and New Year's day.

"Get a regular update so that the software could detect the presence of the new virus before any infection occurs". The viruses affect computers in a number of ways, including wiping out all data stored in a machine. It was intended to appear to the unwary users to be a Y2K or millenium bug problem, by not showing up until the new year.

The viruses share the common trait that, on arrival, they do nothing but check the year date on the machine's battery-powered internal clock. As long as it is not 2000, they will remain dormant. But as soon as the computer is switched on after on the eve or New Year's day, the viruses will go to work and deliver its 'payload'.

Viruses are computer-code writen to do damages to computers, usually spread as files attached to e-mails. When the file is opened, the the virus copies itself onto the computer. Computer users must run the virus scan programme on all downloadable files and software applications before installing and executing them on the computer.

Do the same for all e-mail attachments before opening or executing them even when it comes from a known person or source. If in doubt, delete the e-mail, including those those that are sent to the Trash folder. Computer users are also advised to configure the anti-virus software to automatically scan on all e-mail attachments and downloadable files before being executed as a precaution.

American anti-virus company Network Associates' group marketing manager Sal Viveros said: "We have seen postings on some of the Usenet groups where they are discussing on how to use the Y2k to hose the viruses." So far, Mypics has been detected by anti-virus companies as the most destructive virus during this period.

It will disrupt the internal clock after Jan 1.