HOW TO: Install the HQd Meter Virtual Serial Port Driver (Win 7)
The file that is required is hqd_vcom.inf (in a zipped file, save to your computer, right click on it from Windows Explorer and select "Extract All...". There only one file in it.).
This file can be copied into the c:\windows\inf folder (you may need admin rights to be able to do this).
Windows 7 opened a window that asked if I wanted to "provide administrator permission to copy to this folder"? click the Continue button to allow Windows to copy the file.
When you plug in the HQ40d to the USB port (after configuring to use the Virtual Serial method of communication) Windows will create a virtual serial port in the device Manager. See the following image:
On my computer it shows at COM3, yours may be different, however, the software will scan all serial ports until it finds the device. If you leave the device off or forget to plug it in, it the application will remind you to check these.