So this external hard drive has its own power adapter. Since the drive is no longer turning ON, then definitely, the problem is the power adapter. If the drive is turning ON but cannot be detected by the computer, then the problem is the USB cable.
So I suggest that you buy the power adapter for the drive first.
Here is a sample listing where you can buy it:
And this one:
They are the same adapters, 12V, the only difference is the number of pins.
I hope that helped.
Please remember to rate my service positively (3-5 stars/faces) if this helped. Tips are always highly appreciated!
If you need further assistance, please do not rate me negatively with 1 or 2 faces. Instead, please reply to me so that I can help you further.