I have a problem with my Arduino Uno rev3, which suddenly started to overheat near the small, black, square element next to the circular cable power input port, isn't recognized by Windows 10 (I have the drivers installed, it was working just a while before it broke) and, what is strange, the internal diode (labeled L, next to the digital port 13) is always on. The PC doesn't even notice that any device is plugged in, the arduino IDE doesn't see any active COM ports (the menu option is grayed). The usb cable supports data transfer and is not broken. The arduino was working a while before, I have the drivers and I tried restarting the PC. Now I cannot upload any program to it, neither can I flash the bootloader. What can be wrong and is it possible to fix it?