Somehow the USB driver for V5 brain is gone. And the reinstallation is not working. I find the following log in C:\Program Files (x86)\VEX Robotics\V5Drivers, driver install log.txt:
Microsoft PnP Utility
Processing inf : usb_vex_v5_brain_serial.inf
Failed to install the driver : No more data is available.
Total attempted: 1
Number successfully imported: 0
I tried on both Win 10 and Win 7.
Can anyone help? I did Google search online but cannot find much useful info.