Hi Dan,
The COM port is displayed in Control Panel / System / Device Manager when the driver is installed correctly and connected to the machine. You can check this by looking for Windows Driver Package - STMicroelectronics (usbser) Port in the Control Panel / Programs list. If not, install dpinst_x86.exe manually in the Program Files / STMicroelectronics / Software / Virtual comport driver / Win7 folder.
There may be a conflict between driver programs, and a program called USBDeview will help you remove the faulty driver and install the correct one. Notice what USBDeview tells you when you plug the USB into your device.
USBDeview displays all device connections used since the system was installed, so be careful not to delete the connection in use.
I hope this description helps.
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Gyula HA3HZ
HA3HZ