RAM (Random Access Memory) does not store the instructions to start the computer up this process is done by the Read-Only Memory (ROM-BIOS).
RAM is used to store information so that it can be accessed quickly. It is the main memory of a computer and it is used to store data that you are working on as long as the computer is on, but is lost when the computer is switched off. RAM is known to be volatile. It allows you to switch between windows that you have open, it also stores the modules that are needed to make your application work.