i got two arduino uno and 1 of them can be recognized by my windows but another one is not being recognized by windows.Do anyone of you know how to fix this problem?
Both official Arduinos? If so, send the faulty one back if you just received it.
If both worked fine before, I think you can reflash the bootloader and even the 'USB micro'.
One of the UNO are official boards and it could work but the other one I'm not sure.
The unknown UNO board and another arduino2560 could be able to work yesterday but after i connect them again to my computer on the next day, they have LEDS turned on but not able to detect COM port.