Some hard drives expect to use SATA power connectors. They are thin and flat. If you for whatever reason don't have any 4 pin MOLEX connectors, then you should have SATA power connectors definitely.
It is hard to really help you since its so hard to tell what parts you even have, but look for a flat black connector on the PSU and try to put it in there. That is the best i can tell you unless you make it a little easier on me here.
Line breaks and organization are your friend. Try this format:
Processor Maker Processor Model
Motherboard Maker Motherboard Model
RAM maker RAM model
PSU maker PSU model
Video card maker video card model
case maker case model
hard drive maker hard drive model
cd drive maker cd drive model