HD EXTERNO NÃO APARECE NÃO RECONHECE PC

#hdexternnoappearspc
There are several reasons why HD does not appear on PC
 hard disk is not formatted correctly;
hard disk does not have a letter defined for the partition;
 external hard drive has a hardware failure;
 USB cable connected to the computer is defective or bad contact;
The USB input is failing and does not detect the HD you are trying to connect;
 Current hard drive 'driver' is out of date
In case of error understand this.