Zadig is a program that let's you update or replace device drivers for specific USB devices on Windows. For Proffieboards, we can Zadig to install a driver that lets us talk to the STM32 BOOTLOADER. However, it's easier to just use proffie-dfu-setup.exe. If proffie-defu-setup.exe doesn't work, or you just prefer to do things the hard way, here is how you do it with Zadig:
Options -> List All Devices
STM32 BOOTLOADERfrom the device dropdown
0483 df11, if it is not, do not proceed!
WinUSB (v6.1.7600.16385)as new driver
Done. Once zadig has been run, you shouldn't have to do it again. Your computer should remember what driver to use for the proffieboard bootloader from now on.
Note that on Windows 7, you will probably also need to update the ACM serial device driver, but that is done with a separate program.
Zadig doesn't have an undo, or revert button, but if you run Zadig on the wrong device, here is how you revert it: https://github.com/pbatard/libwdi/wiki/FAQ#Help_Zadig_replaced_the_driver_for_the_wrong_device_How_do_I_restore_it