I have no reason to suspect that this Win7 PC is infected.
I always have realtime protection and updates running with Avira & Malwarebytes
This is what I get when I scan with Avira. (Heuristics set to default - medium)
I didn't run any repairs.
[DETECTION] Contains suspicious code HEUR/Modified.SystemFile
[NOTE] The detection was classified as suspicious.
[WARNING] The file was ignored.