Wiltshire businesses are being warned to watch out for the devastating effects of computer viruses and to take defensive measures to protect themselves in the event of a virus attack.

The MyDoom computer virus has made it into the record books for being the most widely circulated virus of all time, and Business Link Berkshire and Wiltshire has found that last year well over half of all UK businesses were caught out by a virus attack.

More than 90 per cent were using anti-virus software but fewer than 60 per cent updated their software at regular intervals.

"The key to minimising the risk of infection is to have a multi-layered defence which starts with educating users," said Andy Poulton, e-business adviser and member of the ICT team for Business Link Berkshire and Wiltshire.

In the first three months of 2004 the viruses MyDoom, Netsky and Bagle infected more computer systems than ever before, costing businesses in Wiltshire money, time and inconvenience.

The result of virus attacks range from minor interruptions to business to the wholesale deletion of files, the corruption of data and wiping of hard drives.

Wiltshire businesses have endured financial loss due to downtime as systems are cleansed, lost business and credibility, as well as the ongoing costs of preventing future attacks.

Mr Poulton said: "Computer users need to consider any e-mail that arrives with an unexpected attachment as a risk and delete accordingly."

He said anti-virus programmes should be installed on all systems and updated on a weekly basis.

For information and advice on all issues relating to running or setting up a business, contact Business Link Berkshire and Wiltsh1ire on 0845 600 4141.