Originally Posted by
Pob255
Most cards that are double height is simply because of the cooler, they don't actually take up additional slots on the mother board, it just means you could not put a card in the slot below the graphics card (or above depending on case)
although if this is the case I can see the problem.
You should be able to use a double height card, as long as it's not designed to blow directly out of the rear of the other slot.
What you'll have to do is, if it's got a double height rear plate, ether trim the back plate or unscrew it and use your old single size backplate (if the connectors are in the same place) or could try contacting manufactors/re-salers and asking for a single height back plate.