"Hard Drive is now not connected to a PC"
So are you trying to connect a desktop hard drive to a Desktop, or to a laptop?
To a desktop you just need a simple sata cable to plug drive to motherboard and your PSU hopefully has another Sata power cable.
If a laptop then you need a usb type adapter like USAFRet suggested.
If you are copying the whole drive or think you might use it again, the USB 3.0 ones will allow the drive to max out (80-110MB/s) while a USB 2.0 will top out at around 60MB/s.