Intrusion attempt by localhost was blocked Trojan.Zbot Activity 15

Curious about the attached alert. It was concurrent with running “Hitman Pro”, and I'm hopeful it's unrelated. I had recently been battling a rather sever bout of nasty malware, and between Norton and Malware Bytes I felt I had it under control, though several times I feel there is something lurking in the weeds. I have used Hitman Pro several times before and it discovered things both Norton and MWB missed. Is it just odd coincidence that this alter popped up when I ran Hitman, or is there something else going on? Hitman seems legit, has a decent reputation as a second opinion scanner,  and has fairly good reviews from the volunteer sites. By the way, recent full scan with MWB also shows up clean.

This is all after I recently did hard drive wipe (Boot and Nuke) and reinstalled windows. I have run every known root kit scanner and nothing shows up. However, for Norton to identify this, it makes me think it's time for a new mother board....