Difference between Virus ,worm and trojans

The most common Misassmption in computer terminology is wether to call a trojan virus or worm.
what is virus,what is a worm.While the words Trojan, worm and virus are often used interchangeably, they are not exactly the same.viruses worms trojans all are malicious programs which adversely effects the behaviour of computer.
What is a virus?
A virus is a computer program that alters the way the computer operates.A virus is a program that replicates itself on computer systems, usually through executable software, and causes damage.
 A virus can spread from one computer to other computer by opening a virus infected email atachment,clicking on a malicious link,transfering files from one to other.It will often place its self in executable paths there by decreasing cpu efficency.
What is a Worm?
A computer worm is a self-replicating malware computer program. The uncontrolable replication consumes sytem resources slowing or in some cases even aborting other tasks.
It uses a computer network to send copies of itself to other.It uses network flaws to spread.
This is in contrast to viruses, which requires the spreading of an infected host file. Although worms generally exist inside of other files, often Word or Excel documents, there is a difference between how worms and viruses use the host file. Usually the worm will release a document that already has the "worm" macro inside the document. The entire document will travel from computer to computer, so the entire document should be considered the worm.
Ex:prettypark.worm
What is a trojan Horse?

Trojan is a malware that may appear to be legitimate but infact it does malicious activities .It access the users Remote information.Unlike viruses it doenst replicate causing the system to work slow(reducing the processing power,cpu utilization) but they can make a hell of job .Trojan alters the behaviour of computer by uncontrolable popups,adware
These trojan horses are used by hackers to steal the personal information.

Removing a trojan file without using trojan remover software

Trojan is a malware that may appear to be legitimate but infact it does malicious activities .It access the users Remote information.Unlike viruses it doenst replicate causing the system to work slow(reducing the processing power,cpu utilization) but they can make a hell of job .

There are several different types of Trojans: 

*Remote Access Trojans (RAT)

*Backdoor Trojans (backdoors)

*IRC Trojans (IRCbots)

*Keyloggers.

A trojan may modify the behaviour of the system such as uncontrolable pop ups ,adwares etc

it may steal your personal information .

so you should be need careful in dealing these trojan horses by using antivirus and spywares by regularly updating them

Also by Trojan remover.

Here is an interesting thing to deal with these trojans,we can delete trojans without any software.

follow the below steps to remove trojan

*start the computer in safe mode(by pressing F8 at boot time)

*start -->search:

search for the trojan by typing its name ,if you find any of such thing, just delete it.

or

*goto start-->run-->regedit

Now navigarte the bleow registry options:

*HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

*HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

*HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\MSConfig\startupreg 

look for the string Trojan in the right side column,if you find trojan delete it.

-->Next turn off System Restore ,Right click on My Computer-->Properties-->System Restore-->Turn off System Restore-->apply.

*restart the computer

*by following same procedure Turn on System restore

*now your computer is free from trojans

hope you like this ,plz do comment if you want to know anything more.

Restart your machine and turn on System Restore-just the reverse way by which you turned off System Restore.

After these steps restart the computer.