While the battery may not be the root of your problem, you can find a replacement guide for that here and a replacement part here.

Unfortunately no. This laptop's keys need to be replaced as a keyboard all together and not individually. You can find a replacement part here and our guide to keyboard replacement here

When a laptop or computer first powers on, it goes through an initial set of diagnostic tests to make sure everything under the hood is working properly. These tests are called POST (Power On Self Test). When a test fails, the user is notified via POST codes which can be lights or beeps. 7 beeps are used to indicate a CPU Cache test failure. This can be a processor failure or motherboard failure. For this I would suggest you reseat or replace the CPU/motherboard. You can find a replacement part here.