Thanks, Techno Mama, for sharing your configuration. Our own Windows 7, also (x64) 64-bit is the favorite computer system used in our home beside two other systems, 8.1 & assorted linux distros vying to win the Gold Medal for OS(s)!
As a person with advanced experience, what I'm about to suggest may not appeal immediately to your sense of independence and knowing ability to both locate and deal with problems yourself. By creating a new thread here:
you may experience a more thorough screening of the trojan than you have been able to fully accomplish on your own. It couldn't hurt, and likewise I had received help from one of our expert volunteer malware eradicators, shortly after joining near the start of the year, for my then XP system which from that point forward performed better until the day it was retired. I hope all goes well with fine tuning your system, then later choosing the AV that right for you!