Replaced internal keyboard, fn keys are different. How to fix?

Hey guys, first time posting on this forum. I have a santa rosa macbook pro 2006 I think. I replaced the old internal keyboard with a new one but after installing it I noticed the fn keys are in different locations then the original one. This is causing some issues where if I press the volume up button I get the expose desktop button function.

Is this anyway to remap or fix this? Its interesting that only the fn keys are different, nothing else. Would reinstalling the OS make a difference--I know it usually asks you to press the button next to space bar to figure out what keyboard you have..Just a thought.

Any ideas? Would it be helpful to get some pictures?