If your computer is infected with a Trojan horse and you tried everything to get rid of it but it is still there, here are some helpful tips to remove it once and for all. A good way to get rid of the offending malware is to install the ComboFix while also making sure to have an up-to-date antivirus program installed. Incidentally, ComboFix is freeware you can download and install for the sake of scanning your computer for all known malware, Trojans included. It's quite handy because it's free (it's not a trial version of any program and you can keep it in your computer indefinitely).
ComboFix can also immediately spot your problems that could assist your antivirus in its functions. It can even clean infections in an automatic manner like most antivirus programs, with the caveat that it includes a handy report that you can post on forums in case you're dealing with a particularly nasty infection. Don't forget to use propriety antivirus in case ComboFix fails to remove the Trojan in question; all the same, ComboFix is a highly recommended freeware app thanks to its reporting capabilities and cleanup features for most known malware. You should also boot up your Windows in safe mode for a better chance to remove the malware.
Another way to deal with the Trojan is to have a clean computer handy and connect your infected hard drive to the secure computer. From there, you can scan it and clean it of all traces of the malware. Furthermore, you may need to reboot your computer several times during the process. It might be a good idea to go find a local technician or a web advisor in case mere virus scanning doesn't work and outright reformatting of your computer is called for. Just don't forget to scan your files before backing them up to ensure that you don't end up with a copy of the Trojan. Finally, always make sure to only visit trusted websites and run downloaded files from trusted sites.