When connecting the board and running the Zadig program, some Windows PCs may return "driver installation failed." I coudn't find the solution from their download website. So I started the drscl first. Apparently it shows: Successfully scanned, but no boards found. Therefore I checked the Device Manager. A breakdown warning triangle appears under the serial port...
The possible solution may be found here.
Infact, the WinUsb driver has been in existence in your PC. One can just follow the instructions here:
In the wizard, somehow the default setting displays Microsoft Device on the Top of the list and replaced the WinUsb Device. You can easily re-load the WinUsb Device. Just ignore the WARNING from the device manager. The board should work fine now.