A Trojan horse is an application that appears to have a benign purpose but actually performs some malicious function. How do Trojans get onto our systems? What is the purpose of a Trojan and why do people create them? What is the most effective way to remove a Trojan? Recommend at least one tool to help prevent Trojans from attacking your system.

1.Trojan comes in the form of computer game downloaded from a hijacked website.Trojan assist unauthorized access to the host system.

2. Purpose  is the trojan is that steal personal data,password,credit card number.Trojan also  decieve you in logging and executing the malware on the device.once it installed it can perform,for this desogn it.trojan can not replicate themselves as trojan does.

other purpose of the trojans are:

• spying
• creating backdoors
• slow computer
• language seting change

3. way of Removing trojan

•  Identify the trojan
• Disable function system restore
• Restart the computer
• go to add or remove program
• Remove extension
• restart system in safe mode
• need to disable process that are associated with trojan virus.

Tool that are used for prevent Trojan is Avast. This is provide the 

Step-by-step explanation

Trojan is a virus/malcious code that are comes in the form of email/snippet-code after download and install that take control of the system.