Ok try this:
open Control Panel > System > System Restore.
Now disable System Restore (note: you will lose all restore points).
Shut down the pc and re-boot into safe mode.
Run your antivirus program again.
A good idea whilst in safe mode is to rn your various antispyware progs also.
Once all this is complete re-boot in normal, go back into Control Panes and re-enable System Restore.
You will probably find no that the AV has been able to eradicate the trojan. Worthwhile at this stage is to run a registry cleaner to clear out any remains from the registry.