Only 1 cable on it, it connects to the motherboard, you were no help so I had to make a topic

Top one is a IDE power connector.
Bottom on is a SATA power connector.
You probably have a SATA power connector cord.
There is a SATA power cord (Several of them actually) coming from your Power Supply inside your case.
Find it, and put it into the L shaped slot on the back of the harddisk.
If you do NOT have a SATA power connector cord, your PSU (*Power Supply Unit) should have come with one of these;
