WD Passport 1Tb

My Passport works erratically but now, most of the time, it is not recognized by my laptop. I have 700 GB of information. It seems the disk does not receive enough power and the engine stops. Compared to my other Passport (500 GB), the plug is smaller. Could you please help me? Any ideas on how to retrieve the info. Has the Passport become useless? Or can I send it somewhere to repair? This is my third Passport, and  the largest, but I have never had any problems of any kind before.

Are you connecting the drive in the USB ports of the on the back of your computer? What OS are you using?