If you are using the memory expander slot, you need to be careful in putting in the card as well. I have see 1 bent pin cause major headaches because the bent pin does not go where it needs to go to and sometimes short out another pin. Straightening a bent pin can be dangerous as well as it might break while being bent back into place.

One needs to line up the card straight with the connector and push it down gently until it hits bottom and keep pressing for a while. As crazy as it may sound, I seen one slot (not a Mac memory slot but a PC AGP slot) spit out a card if this is not done. You push in the card and release it, and a few seconds you see the card slowly rise up and then "POP!" it jumps off the slot! Talk about having a ghost in the machine! But pushing the card in and holding it down for a while seems to make the slot happy to keep the card in place.