A Trojan is a computer Malware that disguise itself as a legitimate program, hence the name Trojan derived form “ Trojan Horse.” Most Trojan will try to perform malicious modification such and deleting files, key logging, changing programs, etc. Trojans are very common to be infected by uses which use peer to peer networking, gambling website as as well as porn websites. There are very good Malware programs that can detect most Trojan by performing a full scan.