Wd my passport 0748 not initialized because of an i/o error

SOURCE: WD 1TB My Passport Essential is unusable.

This error comes up when the drive is formated by a different operating system, and yours can not read it. You will need to format it to be read by your current system, but you will lose any data on it. The only other option is to find out what it was formated for, Windows or MAC, and hooking it up to that computer.
With a Windows system, once you hook it up, open explorer (not internet explorer). You will see that drive on the right side, right click on it and choose the format option. Once it has been formated, you will be able to use it.