I would recommend SpyHunter to fight trojans and VIPRE Anti-virus for getting rid of viruses and other malware which you might have gotten. I've tried the software myself some years ago, and Spy Hunter software could remove trojans with few other software could find.
So if you got very important data on your Windows system, I would recommend to consider paying for software in this. Otherwise, if free software can do the same OR more, then it's a waste of money. I'm not sure at the present which is best? or migrate over to Linux and be safe any way..