PC users have been urged to scan their computers before 3 February to make sure they haven't been infected by a destructive virus which is set to activate for the first time on that date.

Called Nyxem-E, if it is not removed, it will do its best to delete Word, Powerpoint, Excel and Acrobat and other common files on infected machines.

The virus, which also goes by the name of MyWife, Blackworm, Kama Sutra, Grew and CME-24 virus, first surfaced on 16 January. It arrives as an attachment to emails promising pornography videos and pictures.

Once downloaded to a person's PC, the virus self replicates by harvesting email addresses and sending itself on. It also has a network worm element so it will look for any vulnerable computers on a shared network.

Nyxem is programmed to cause as much havoc as it can by targeting 11 different common types of file on infected machines on the third of every month. It will also attempt to disable anti-virus software to stop it updating and can also disable the mouse and keyboard on infected machines.

The subject line and body text can vary but anti-virus companies have been stopping thousands of copies. They have also been able to track the number of infections, which stands currently at about 300,000 machines worldwide because the virus reports every fresh infection back to an associated website according to security firm Lurhq.

Leading security sofware will protect consumers against this virus and remove it as long as it is up to date. People are therefor being urged to update their anti-virus software and run a full disk scan to make sure they haven't been infected by the virus.

If they don't the virus will not only damage their files on 3 February but continue to activate each month to repeat the problem.

Jason Steer, technical consultant at mail filtering firm Ironport, warned Nyxem had the potential to be a big problem for consumers. He said 99 per cent of consumers do not regularly back up their data or update their anti-virus software.

"We are seeing an upward trend in malicious emails. There are two reasons behind this. One is for criminal activities, others such as Nyxem are because the virus writers may be bored and doing it just because they can.

"They will continue to do this as long as PCs remain vulnerable because people don't back up their data and layers of security software. Consumers should ensure they keep their anti-virus software up to date and back up important documents to DVD or CD," he said.

A removal tool can be downloaded from here