We all know that there are many quality trojan removers available in the market.But you can easily remove a trojan file without using any third party softwares.
Start your computer in Safe Mode.
Start>Search :-Here you start searching by typing the name of the trojan.And if you find any just delete it.
Now navigate to the following registry keys:-
Expand all the keys by simply clicking (+)signs.
Now look at the right pane and delete any string having the trojan file.
Now close the registry editor.
And finally don't forget to turn off System Restore [Right click on My Computer>Properties>System Restore>Turn off System Restore>ok/apply.
Restart your machine and turn on System Restore-just the reverse way by which you turned off System Restore.