IT WAS a short-lived thrill when Singapore Management University student Justin Low, 22, received an e-mail titled A Valentine's Day surprise last February.

He opened it with much glee, only to find out that it came from an ex-classmate he had not seen in years, rather than his current girlfriend.

Your friend wants to send you a Valentine's Day greeting; click on the link below to read it, the e-mail said.

Mr Low recalled: "I hadn't the slightest interest in that classmate and still don't, so I thought something was amiss."

He said he was sceptical because of a virus attack on his computer barely a year before.

He had to reformat the computer hard drive.

The upcoming Valentine's Day and Chinese New Year festive seasons are usually exploited by cyber-crooks to spread their malicious viruses by disguising infected e-mails as e-greeting cards, computer experts warn.

The latest variant of this tactic - known as "social engineering" - is the Storm virus, which global IT security and control firm Sophos says makes up 8 per cent, or one in every 12 e-mails, they see.

US-based information security database, SANS, reported that the virus appeared during the Christmas and New Year seasons with appropriately themed variants, but the Valentine's version makes an especially vicious tug on lonely hearts.

It sends out e-mails to potential victims with mushy titles such as Falling In Love with You or Special Romance. The body of the e-mail carries a link to an IP-address based website, hosted on one of the many compromised PCs in the Storm network of infected computers.

The website displays a large red heart and a message that "your download should begin shortly" as it installs a virus onto the visitor's PC.

Sophos analysts believe that the worm code will download further malicious code from the Internet onto your computer, subsequently using it to send spam to names in your address book on behalf of hacking gangs.

It could also attack and disable your anti-virus software and open up "backdoors", or unprotected ports, on your computer that hackers can tap to access passwords and other documents, said Mr Wayne Ho, an IT administrator at Singapore IT consultancy firm Erlins.

"These viruses prey on human curiousity so as long as people can overcome that, their chances of getting infected are lower," he added.

Watching out for the way friends word their e-mails, as well as checking with them before opening any file they have sent is key to prevention.

Said IT consultant Mr Kee Qing Hai, 24, who tended to three customers who were victims of a similar virus last year:

"There are many free anti-virus programs out there for people to download. But it's not enough to just install them, you must also frequently update these programs to make sure you are safe."