Hi Chuck,
i see you need to install a driver on windows 7 so that your computer can see nanoVNA. To do this, download and install en.stsw-stm32080.zip (DfuSe) or STSW-LINK004 (ST-Link) or en.stsw-stm32102.zip (STM32 Virtual Com Port driver). DefuSe or ST-Link is required for a firmware upgrade.
After installation, plug the nanoVNA connector into your computer's USB port. Use the USB cable (not OTG) supplied with the nanoVNA.
I don't know what the usb connector of white nanovna.
You can see in the device manager of your computer that it is present at COM & LPT.
If not, a little utility (USBDeview) will help you to remove the faulty driver.
To run nanoVNA-Saver on Windows 7, you must have the SP1 Service Pack installed and MS VC ++ multipack (2005-2017) installed, then the windows exe version of nanovna-saver will work. It starts up slower when you first start up, later it is faster.
Hope I was able to help with the solution.
73, Gyula HA3HZ
Gyula Molnar