Arduino Uno power problems

I need your help. I was working with my Arduino Uno and than it stopped working. I found that the green power LED is irregularly blinking. So program inside Arduino is starting over and over and never get to anything. I changed USB cable, tried others USB ports on my PC, but still the same. Also when I check Devices on PC, Arduino is blinking that is conected for a while and than not. All that means that I cant upload a new program.

I havent found any damage on the board itself. Can it be caused by dust?

Thanks for replies

do you have a mains converter to usb? if so try plugging that up to the arduino. It will test your usb socket on the computer.

Can your measure the 5v pin?


Well, I tried every USB port on my computer with Uno - still same - and than I conected Arduino Mega and that was OK. So, I pressume that something is wrong with Uno.

Is anything feeling hot on the card? There is resettable fuse in series with the USB power - if something on the card is running hot, that fuse could be tripping, cooling off and resetting, then tripping again.

Nothing hot...