If you receive an electronic Valentine's Day greeting from a secret admirer, be careful. Opening a virus-infected greeting could leave you with more than emotional scars.

Valentine's Day is one of the busiest days of the year for spammers, who prey on people's desire for love, using it to spread malicious computer viruses. The risk of getting more than just love messages in your inbox is high.

Security company Panda Labs has recently noticed a massive increase in a virus worm named Nurech.A . The malware is hidden in email messages named 'Together You and I' and 'Til the End of Time Heart of Mine'. The company also advises people to stay clear of opening attached files named 'postcard.exe' or similar.

Sophos warns about emails offering jewellery, lingerie, or chocolate ahead of Valentine's Day. Its researchers said these often come from spammers trying to lure users to open malicious emails.

Symantec has also reported an increase in virus activity . The security company has spotted a large scale spam attack which contains a Trojan. The Trojan is an updated version of the already known Peacomm virus, also known as Storm Trojan.

The spammers behind the newer version have attempted to disguise the program for anti-virus programs. Symantec pointed out that so far they have been unsuccessful as its anti-virus filters have spotted the viruses.

The good news, Sophos says is that users are increasingly suspicious about opening emails from untrusted sources. Only five per cent of computer users admit to buying products via spam, according to the company.

Special occasions such as Christmas, New Year and Valentine's Day plus big events like the World Cup are often exploited by cyber criminals attempting to spread malicious viruses and code.