Two antivirus firms, McAfee and MessageLabs, yesterday issued a warning to all Windows users that a powerful new virus could be on its way to their machines.

The Goner virus, which has been causing havoc with computers in the US and France this week, was first detected in Europe yesterday morning and has now hit Britain.

According to McAfee the mass-mailer worm is distributed via an email simply titled "Hi". The body of the email reads "How are you? When I saw this screensaver, I immediately thought about you. I am in a harry, [sic] I promise you will love it!"

Some PC Advisor staff spotted it was a virus because the misspelling of 'hurry' didn't tally with the sender's usual way of writing. This kind of suspicion is often encouraged by antivirus firms.

The payload in the virus is not self-activating and requires emails to be opened to activate it. Once opened the worm can delete files and then emails itself to every address found in the persons address book.

"The problem is that most companies' firewalls don't stop screensavers as these files are generally harmless," said Sal Viviros, marketing manager at McAfee. "This virus is devastating. It has caused whole servers to go down because hundreds of inboxes have been hit."

McAfee has detected 68,000 incidents from its online scanning system, which is the largest it has seen since the Love Bug virus.

Anyone running Microsoft Outlook Express and whose computer supports Visual Basic Scripting is a potential victim.

Microsoft has not yet issued a patch for the Goner virus and has urged users to be vigilant.

"There are more and more viruses attacking our systems and it is vital that we are aware of their existence and know how to handle them," said Microsoft.

Antivirus firm Computer Associates has branded the worm high risk.

"Like many other virus threats, Goner uses social engineering to induce users to unknowingly activate it," said Ian Hameroff, business manager at Computer Associates. "Goner can be stopped in its tracks by a combination of common sense and the right tools."

Most of the antivirus major players have issued virus defence DAT updates plus manual removal instructions, so PC Advisor's advice is to update your DAT files now.