Second-hand computers available at online auction sites and computing stores may still have enough information on them for internet fraudsters to steal IDs and other sensitive details, despite efforts the previous owner may have made to delete all confidential data.

To highlight these IT security concerns, Navigant Consulting purchased three computers on the second-hand market - and was soon able to uncover important personal information on one of the machines.

Despite having reformatted the hard drive and installed a new operating system, the firm identified the machine as being from a community college and found staff budget and payroll details, as well as bank account information and students' benefit applications.

"This level of information potentially put students, staff, suppliers and the college as a whole at risk from fraud," commented Andrew Durant, head of Navigant Consulting's fraud investigation team.

"The message is simple: if you can't securely delete your data, don't sell your computer.

"It is possible to download software from the internet to securely wipe data from your PC, or better still, take it to a reputable reseller and ask them to do it for you."

According to recent survey by Connect, the two biggest IT headaches for businesses were 'everyday hassles with IT' (37 per cent) and 'security concerns' (32 per cent)