If the board you have is much like the SLI board I have there is a selector circuit board that you have to check to make sure it's set for 1 or SLI mode graphics. Mine looks much like laptop memory and if it's re-inserted one way it's 1X16PCIE if the other 2 SLI mode. Maybe yours has the same and it's wrong?
AS to the powersupply comment, he stated it was running prior so unless this new board draws WAY more amps then the prior I feel he should be fine.
I am pretty sure A8N32-SLI doesn't have that, I have 2 PCI-E 16x Phisical (16x electrical) doesn't need that SLI switch.