I recently bought an Uno and got it up and running successfully on both windows and ubuntu. A couple days ago, it stopped communicating with my windows box.
First things first:
- Windows 7 64bit,
- the driver's are installed correctly (Windows shows "Arduino UNO R3 (COM4)" in the device manager),
- I have 'Uno' and 'COM4' selected in the IDE
Right now, there's a sketch loaded which blinks the LED and sends 'Hello world' through the Serial port at baud 19200 every 2 seconds. This works fine on my linux box. The LED lights up, I see the tx light blink every 2 seconds, and I can see 'Hello world' repeated in the Serial Monitor.
When I plug the Uno into my windows box, the board powers up, the device is recognised, and the LED begins blinking. Except this time, the tx light does not blink. The Uno won't send anything over the serial port. That's also reflected in the verbose upload output: avrdude sends data but receives no response from the Uno.
What gives? I can switch COM ports using the device manager and everything happens the same as above so my windows box is recognising the hardware. And everything works on linux, so the hardware is definitely capable of transmitting data.