The boss of a company held to ransom Attack.Ransom by computer hackers is warning others not to fall victim . Two years ago Stuart Kettell ’ s company Kettell Video Productions was targeted by hackers who encrypted all his files and demanded money Attack.Ransom to decrypt them . Stuart Kettell may be best known for his light hearted charity fund raising challenges but this cyber attack was no joke . The hackers infiltrated computer systems at the Warwick based company . They made it impossible for staff to see any of the company data and demanded Attack.Ransom £1,000 in online currency bitcoins to put matters right .