Are you running 2 monitors? As you have 2 cables plugged into the card.
If you only have 1 screen, you only need 1 cable.
I started off helping you try and get a new card as it looked like yours was bad. But your links suggested you should also had a built in card, which might have saved you from buying a new one. But now your picture showed you don't,
BUT NOW
You've got me wondering on your setup, and your card might be fine, just setup weird.
From what i can find, the 220 should work as it draws about the same as the 8600... Your 8600 came from the factory like that.
Also, reviews are showing some pretty low power draws, so you should be fine.
I know this is fustrating for you, but I like ensure your old stuff is dead before spending money.