go to local stationary shop buy a duct tape & stick that drive in any free drive place connect SATA & power.
don't stick desktop SATA/molex power cable directly on the laptop HDD. my friend once did the same instantly killing the HDD. most likely laptop HDD requires much less power which can be provided even by a USB port.
5V vs 12V , right ? They also have different RPM speed , 5400rpm vs 7200rpm.