The whole boot process of computer can be summarized in 4 phases.1. BIOSIn the 70's  read-only memory(ROM) was invented. The boot program is written into ROM, the first thing the computer does is to read and execute this program when it's powered on.The program in this chip is called "Basic Input/Output System" (BIOS).1.1 Power-On Self-TestThe BIOS will first check whether the computer hardware can fulfill the basic conditions for booting up, this process is called Power-On Self-Test, simplified as POST.If the hardware has problems, the mother board will produce different beeps and the bo...