Is it OK to connect HDD on DVD connector?

[Dia]

 

First, I am not a game player. First time to touch such a good PSU as RM650x.

Could not start my old PC normally. Some say it was a bad PSU. Bought a used RM650x for testing.  

Had HDD connected to one of the 4 connectors, 2nd from PSU, had power on, the PC did not start. Tried the other 3 connectors, PC did not start.

Connected HDD to one of the 3 connectors for DVD, my old PC started and ran 4 hours normally. 

Questions:
1. Is it OK to have the HDD have on DVD connector and use the PC everyday?
2. Does BIOS recorgnize the HDD and does Windows installer recorgnize the HDD when to do an OS reinstallation?

Thank you.