So if I understand correctly, the Stargate is working fine EXCEPT for not being able to communicate with your PC. If that's the case and you've verified that the serial port (or USB adapter)and cable on your PC is good, it could be a bad RS-232 serial chip which is an easy fix.
But if you're using COM1 for the PC and the X10 signals are still being sent from the SG1 to the TW523/PSC05 that's probably not it.
With the WebX installed can you operate modules from a browser? If yes, then the serial port is OK and it's like a problem with the PC or cable.
One other thing to check is in WinEvm verify that the serial port is configured properly. Sometimes that needs to be refreshed. Click Utilities:Options and try different serial ports 1 through 4. If you're using a USB to serial adapter see how it's set up.
Report back with the results and we'll go from there.
I really have no idea what the whining noise might be.