multiserial.ino No Driver

[jhsa]

I tried the Multiserial example on windows 7, using a blue pill board and the arduino IDE.
Windows fails to find and install the drivers.

The same happens also with the following sketch.

#include <USBComposite.h>

const char ManufacturerName[] = "My Device";
const char DeviceName[] = "USB Serial";
const char DeviceSerial[] = "00000000000000000001";

USBCompositeSerial CompositeSerial;


uint32_t counter = 0;
void setup()
{

  pinMode(PA11, OUTPUT);
  pinMode(PA12, OUTPUT);
  digitalWrite(PA11, LOW);
  digitalWrite(PA12, LOW);
  delay(10);
  pinMode(PA11, INPUT);
  pinMode(PA12, INPUT);
  
  
   USBComposite.setManufacturerString(ManufacturerName);
  USBComposite.setProductString(DeviceName);
  USBComposite.setSerialString(DeviceSerial);
  //USBComposite.setVendorId(VendorId);
  //USBComposite.setProductId(ProductId);

  USBComposite.setProductId(0x0236);
  CompositeSerial.registerComponent();
  USBComposite.begin();
  delay(2000);
}
void loop()
{
  CompositeSerial.print("Counter: ");
  CompositeSerial.print(counter);
  CompositeSerial.println(" - Hello World!");
  counter++;
  delay(500);
}