Computer users are being urged to update their anti-virus software to avoid a potentially lethal virus due to hit this Friday.
The virus, which could wipe out thousands of documents, spreadsheets and databases from computers, has been disguising itself in attachments with titles such as Kama Sutra, Miss Lebanon 2006 and The Best Videoclip Ever.
Security experts have named it Nyxem-D, and said it has been spreading since 16 January. The number of users affected is unclear, but the virus is timed to activate on a Friday, and on the third day of every month from then on.
Employees are being urged to scan their machines for Nyxem and update their anti-virus software to avoid being caught out.
It could erase irreplaceable documents and will also try to turn off anti-virus software, attempt to steal information and infect other machines.