Sometimes trojans can hide out in system restore even after removing with your antivirus software.
If you restore to an earlier point at some time the virus could come back.It's also possible for it to reapear without using the system restore.
To be sure of removal turn off system restore ,as this deletes all restore files and any viruses ,then rescan again and turn restore back on.
Bewarned though,you will obviously be unable to restore your pc to an earlier date if need be untill you or it creates an other restore point.
p.s,it's always better to scan for viruses in safe mode.