Arduino not recognized anymore

My Pc won't recognize my UNO R3 Anymore. The LED at Pin 13 don't light up also. The only LED is the power-led. Anyone has an Answer for this Problem?

OK with a different USB-Port it gets recognized and works with it. But when i use the main Power-supply it won't work. It only works when i use the USB-Port as power-supply

What voltage power supply ?

As far as USB ports go stick with USB 2.0 and NOT USB 3.0 unless you put a POWERED USB 2.0 hub between the USB 3.0 port and the Arduino.

Most on here reccomend no more than 9 Volts for the PSU as there have been reports of the voltage regulators popping.

OK i found the mistake i made. Seems to be as i am blind. I used a 19V AC instead of a 9V AC by mistake. So this means my AC-Power-supply isn't working anymore right? Is there any possibility to fix it without replacing the entire arduino?

Some people have reported sucess in replacing the voltage regulator whilst others found that there was a little more damage than just the regulator.

Sort of depends on how far you want to go and if you are comfortable with fine soldering and have the equipment to trace the issue.