300CE- fuel pump

Okay, we've looked @ the fuel pump, it seems it's not getting any juice to it. Does that have something to do with the fuel pump relay, if so where might it be located? Or is that a sign that we definitely do need a new fuel pump.
We've just put in a new radiator (was melted), to find out we need to replace the water pump. How do we get the old one off?
We would like to get the car running, so we can take it to a mechanic to see if its worth fixing any further.
Thank you for your time.
You guys are a big help.
thanks!