There is currently a power cable going into the back of my primary sata hard drive but i want to put another hard drive in but there is not another power cable
in case your in basic terms utilizing it for storage and deploy it as a slavechronic then certain. If it has were given an OS on it you wont be able to apply that because the OS gained't keep in mind that new laptop and may probable blue reveal screen on you.
I would try going to a nearby hardware store or electronics store that deals with computers and explain your situation to them. They can probably figure something out.
Just get an external drive.
You can get a 4 pin molex to Sata power Adapter. heres one that'll power both your hard drives.