It's not completely out of the question that it was something pre-installed by the computer's builder (like Dell, HP, Acer, etc.).
System Mechanic may have already removed it, but one way you can sometimes identify things like this is to look at the Startup tab in Task Manager (press Ctrl-Shift-Escape to get there).
This tab takes the place of what used to require more advanced tools to see, and lets you take a look at programs that automatically run in the background. None of them are required, but of course you might prefer if something like iTunes is always waiting for you to plugin your iPhone so it can spring into action, so you might decide to keep some of them enabled. I usually disable everything but OneDrive (so it can keep my files backed up).
But from here, if you see the ActiveComm program listed, you can right-click the column headings at the top to turn on some additional details and perhaps see what that program is what command line it uses, which can sometimes identify the manufacturer or more details.