Nissan Repair: Starting Issues on 1998 Nissan Maxima, starter solenoid, nissan maxima

Question
My question is a four part question:

A) Replaced the old starter with a new one, hooked everything up correctly. Won't crank. could it not be grounded correctly?

B)Could the start relay fuse have blown?

C)Took battery out and took to part store, charged it fully, still won't crank. Could battery be completely dead?

d) could the alternator went out?

Answer
First, you need to use a digital self powered volt/ohm multimeter. With The meter set on 20V DC, check the battery voltage. Lets say the battery reads 12.6 volts. Memorize that reading. Disconnect the meter and connect the positive lead to the starter's cable, right where it terminates on the starter (the big one that goes from the battery to the starter motor), and the negative lead to a good ground. The voltage reading there it should be the exact same one with the one of the battery. If it's not or there is no voltage reading, then one or both of the cable terminals had failed due to corrosion or loose contact. If this test checks out okay, move on to the next test: Locate the starter solenoid cable, (the small one) and connect a test light to a good ground and the terminal of the small cable right where it terminates on the starter. Have someone turn the ignition to crank position and see if the test light comes on. If it does and yet the starter motor doesn't do anything then the starter motor is defective. If the light does not come on, then, there is a wiring problem between the ignition switch and the starter solenoid terminal. Connect a remote starter switch and see if the starter activates. If you don't have a remote switch, make a jumper cable of same gauge or similar to the original solenoid cable and secure the one end of it on the solenoid terminal. Carefully, touch the battery positive terminal with the other end of it. The starter should activate and crank the motor. If it doesn't then the new starter is defective. If it does, that verifies an open wiring as a mentioned above. Make sure the 2 fusible links that are near the battery's pos terminals are not burnt out and that all the connections are clean, tight and free of corrosion and let me know for follow up.