The steps of POST (
Power
On
Self
Test) can be described in a very complicated way and in a longer version, but a simple order of the operations that your computer undergoes as it boots is:
1. Signal is sent to the CPU, which erases the chip’s internal memory registers.
2. Begins the BIOS, checks CPU by comparing itself with permanent records.
3. A signal is sent all over the computer’s bus system to check whether everything is functioning.
4. Checks the timer, to ensure the system is synchronized.
5. Tests the visual output (monitor).
6. Tests the RAM, and calculates the amount of RAM there is.
7. Checks the keyboard, and if keys have been pressed.
8. Tests all the drives to see what is available.
9. Checks with the CMOS battery and obtains the time.
10. Loads the operating system from a disk.