Sentel plc is a UK financial services company with offices in the south-east and north-west of England. In total the company has five offices in the south east of England and six in the north-west. It currently employs 97 staff. The company has been trading successfully for 17 years. For the year ending 31 December 2005 the company’s fee income was £18.4m and its net profit for the year was £10.1m. During 2006, however, Sentel’s computer system/network was targeted by a number of UK-based groups attempting to gain unauthorised access to the company’s system/network and steal confidential client information. During May 2006 the company computer system/network was severely infected by a polymorphic virus and on 6 May 2006 the computer system/network suffered a complete systems failure resulting in company losses of approximately £655,000
Explain the main prevention strategies and technology tools a company like Sentel plc could adopt/use to prevent or at least manage unauthorized access and virus infection.