Update: All sorted. It turned out I just needed to 'give it some welly'. Hi All, After some research, I bought an ATI Radeon 5770 upgrade pack from my local Apple store to replace my broken NVidia 7300 GT for my 2006 Mac Pro. I've plugged in the power leads, etc, but I can't get the card itself to fit the machine. There's a metal lip on the external-facing port end that's preventing the card from sliding into its slot. I can't find details of anyone having a similar problem. Is there something else I should be doing? Thanks!