When I plug the other one into the same USB port, Device Manager gives the topic error ('This device cannot start. When I plug one into my computer, everything works fine, and Device Manager says it is Com4. Hi, I am witnessing very strange behavior around the same problem: Please, can somebody help me? Thanks in advance. I've pressed the RESET button on the Arduino but nothing helps me. The LED on my Arduino is still working and the ON light is green. It seems the Arduino (or usb cable) is not recognized. I tried it on another computer + Laptop (both with Windows 7), and nothing happened. The software for this device is installated, but it seems it does not correctly work. The installation began and then came the following message: The next hardware is installed: Arduino UNO. In the following list i clicked on Arduino UNO and then on Next. In that list i see Arduino LLC (I clicked on Browse and chose the arduino-1.0.3/drivers/Arduino UNO.inf. In the following list i clicked on Ports (COM & LPT). There i chose 'Looking for hardware and installate automatically. After that I tried in the menu 'Add older hardware'. I enabled in the Menu -> View -> View hidden devices. I neither found 'Unknown devices' in the list.

In the list with devices i tried to find the Ports (COM & LPT), but it was in my list. So i went to the Configuration Window of my laptop, choose Hardware & Sounds -> Device Manager. But i know, i forgot to installate the driver for the Arduino UNO. I searched on the Arduino site (and forum and Google) for errors and troubleshooting but i can't get it working. I looked in the menu at extra-> serial port. Then i get the error: Serial port 'COM3' can't be found. But after that, i've changed the code in the Blink example (i would let blink 2 leds) and tried to upload it. I uploaded it and it seems it was successfull. I opened the Arduino.exe and i opened the Blink example.

I plugged in the USB cable with my Arduino UNO board.

I've downloaded the Arduino Software on the official website, and unzipped the folder. Yesterday i used my new Arduino UNO for the first time. Hi, (im using a Dell laptop, with Windows 7, 圆4)

Install ch340 driver windows 7