It's kind of a stupid question, but I really don't want to go and buy another PSU. I recently bought a second hard drive to add to my system. Problem is, is that I don't have any more connections to use. I don't have molex connectors so that's out of the question. I have these extra slots on the unit, which I really don't know why they are there.
The idea with a modular PSU is most of the cables for SATA or Molex or floppy connectors etc are plugged into the PSU if required and if not required kept in a safe place. (often in a box or bag inside the PC case)
If you don't know where the spare cables are you will probably need to buy a new PSU .
I have seen Molex to 1 or 2 SATA adapters, it seems there are also sata (in) to 2 sata (out) cable adapter