Check that the sound card is fully seated in the PCI slot, making sure 
that the gold-colored connectors are down in the slot.  

If more of the connectors are visible on one side than the other, the 
card is not seated correctly and needs to be taken out and reinserted.
The card is installed correctly when the connectors are almost totally 
covered by the white PCI socket.  Once this is done, insert the 
mounting screw on the metal bracket and tighten it. 

If you are still having difficulty, remove the card and try inserting 
it in a different slot.