If plugging into USB on your Win-7 machine, your serial to USB adapter will need to be Win-7 compliant. Most were...many counterfits (which were plentiful) aren't. We found this to be the largest problem with folks jumping from XP to Win-10.
The takeaway is you'll need to identify the adapter model/ brand and do a web search for Windows drivers. Such are the trials of the old serial-style jib. Alternately, you can find this, with Win-10 compatibility, for ~$12 or less on line.
I hope this answers your question, it wasn't phrased in a way that could mean much else.