Serial port blocked

Hello everyone,

I have an Arduino UNO. It’s some time I have used it, so I don’t really remember what was the last sketch I uploaded, but now I have I problem, I can’t connect it through usb. I have a Win7, Xubuntu and I’ve tried various other methods explained here and mostly everywhere else. I bought another Arduino UNO, so I could load a bootloader onto the broken one. Any sketch I upload on it works just fine, except I cannot connect it to my computer. And once it is powered on, a green led RX is on. Do you know how to “bootload” the serial com. chip? It gets instantly hot under every possible powering of the arduino- not just by usb cable, but by a battery and external power source as well. Is there any possibility to repair it?

Thanks a lot, I hope that I have given you enough info, if not, please ask :slight_smile: