Arduino Uno not turning on

We have an Arduino Uno that we've had for a while but never used before. I tried to use it today, and the green light won't even turn on. I'm wondering how to find out what's wrong and/or fix it, if possible. I've tried three different USB cords to power it. Thanks?

Download the Uno schematic.

Some things to check

The fuse (F1) might be broken; measure the 5V at both sides of it.
Check the soldering of the USB connector on the board.
Check if the LM358 gets hot (it should not).
Check if you can power it from e.g. a 12V power supply.

Help isolate WHERE the problem is....

Does the same USB cable work on another device (phone etc)
How about if you power the UNO via the DC connector...

lastchancename:
Help isolate WHERE the problem is....

Does the same USB cable work on another device (phone etc)
How about if you power the UNO via the DC connector...

There is a jumper to select USB or external power. Check it out.

My Arduino Uno works from USB or external power source through the barrel connector without adjusting a jumper. Other options discussed here:

Have not heard of a jumper needed.

Sorry, oversight mistake. I have a UNO clone by Richduino, this does have a selectable jumper for usb/DC (Barrel Jack)

Regards.

OP seems to have lost his PC as well?
Maybe the ‘during took it down !