Cyber crime is the unlawful act wherein the computer is either a tool or a target or both. Cyber crime is the evil act done by the hi-tech professionals, some, as hobby and as business. In this paper, authors keeping the view in the mind that prevention is better than cure, have describes some preventive measures, also how to detect and prosecute these unlawful activities. Also have given the attention to the new users of the IT act 2000 and offences covered under the IPC section.