If you know the specific Trojan infecting you you may find very specific solutions online ...
But if you don't there are a couple of things I suggest.
The first is to create a
Windows Defender Offline CD (on another virus-free computer and be sure to get the win7 version) and then boot this computer with it and have it run a virus scan.
Second, download TDSSKiller and RKill from our
Freeware DB. If you do not have an anti-virus that will run in safe mode then download, install, and allow to update Malwarebytes Anti-Malware (MBAM). Then reboot your system into safe mode without networking (Reboot and, when it says "Starting Windows," Press F8; If you get a message asking continue in safe mode or perform a system restore, choose continue in safe mode). Now run TDSSKiller and after that run RKill and after that run a full virus scan. The first two will take maybe 5 minutes each but a full virus scan can take anywhere from 30 minutes to several hours depending on your hard drive size and number of files.
Booting in safe mode makes sure only minimal services/programs are started. TDSSKiller is designed specifically to look for rootkits. RKill is designed to stop the stealthing programs that hide/protect/regenerate some nasty viruses. Running these first will help ensure your A/V has the absolute best chance of cleaning up infected files.
