1. Did WL appear to install fully with no errors reported during installation?
On Win 7, I don't think I ever got WeatherLink to install and run correctly, but it was 4 years ago now. On my Windows 10 machine, it reported an issue with (an old) .Net libraries, but they were downloaded installed correctly and the application now starts up.
2. If [1] is OK then are any errors evident in the download.log file?
Yes: "Computer gave up waiting for response from station. Check port setting and connection".
3. If you're using USB mode, have you tried switching to serial mode?
USB mode does not find a weather station. Serial, Auto Detect does not find a Com Port.
A driver issue, I would assume? What do I check?