I assume MDG is something like Compaq/Dell right?
Did it run the computer without the 4 pin connector, or didn't you try yet?
I am pretty sure the second 4 pin connector (near the CPU) you mention is the one I am talking about.
If your computer works without it, don't change anything; if it won't, try pluging the 4 pin next to your 20 pin.
TheMajorMMX - Intel P200 MMX @ 225Mhz - V-Tech (PcPartner) Baby-AT mb w/ Intel Triton TX chipset - Nvidia Riva TNT2 M64 w/ 16MB - 256MB M-Tec SDRAM - Still running.....