I'm leaning toward your Kingwin Kf-252 bk being defective.
For the Powersupply.
.. I'd check the + 5 V rail. 2.5" drives only use the +5 V (3.5" drives use both the +12V and the +5V.
To check the +5V and the +12V is VERY simple. Buy a $18 Digital voltmeter from Walmart. Watch a You tube video (can google "how to Use a voltmeter).
DVMs are very handy, not just for computers but around the home and for cars, and simple to use.
How simple - With Power turned off. Plug the Black meter lead in two one of the center two pins of a Molex power connector. Plug the red meter lead into the end of the Molex connector that has the RED wire. This is Your +5 V and should read between 4.75 V to 5.25 V. The Other end of the Molex connector is the +12 V and should read between 11.6 V anf 12.6 V.
Highly recommend you do this before buying a New PSU. If PSU is NOT the problem, then even with a NEW PSU you could end up with the same problem.