Every PC has built in hardware diagnostics that run when you turn on you PC.
The self test the PC performs on itself when you turn it on is called "POST" (Power-on self test).
It is a bunch of basic tests done during the startup of your PC by the BIOS, the moment you turn on your PC.
BIOS stands for (Basic Input Output System)-- it is the firmware in your PC's ROM chip that controls the input and output functions of your PC; BIOS controls things such as boot up, temperature fan control, your monitor (screen), your keyboard, CPU settings, etc without need to load software.
These basic tests check to see if the BIOS can "talk" to main components of the PC to ensure it is functional and can boot up without problems.
If your PC passes the POST test, then Windows or your installed Operating System will load.
If your PC fails the POST test, Your Operating System may not boot and you will hear beeping sounds.
According to Jean Andrews, the author of "A+ Guide to Managing and Maintaining Your PC", Seventh Edition, published 2010 by Course Technology, Engage Learning-- on page 285:I paraphrased Andrews' lists for the beep codes when POST test fails:
MrSeeker
December 03, 2015
New Google SEO
Bandung, Indonesia
The self test the PC performs on itself when you turn it on is called "POST" (Power-on self test).
It is a bunch of basic tests done during the startup of your PC by the BIOS, the moment you turn on your PC.
BIOS stands for (Basic Input Output System)-- it is the firmware in your PC's ROM chip that controls the input and output functions of your PC; BIOS controls things such as boot up, temperature fan control, your monitor (screen), your keyboard, CPU settings, etc without need to load software.
These basic tests check to see if the BIOS can "talk" to main components of the PC to ensure it is functional and can boot up without problems.
If your PC passes the POST test, then Windows or your installed Operating System will load.
If your PC fails the POST test, Your Operating System may not boot and you will hear beeping sounds.
According to Jean Andrews, the author of "A+ Guide to Managing and Maintaining Your PC", Seventh Edition, published 2010 by Course Technology, Engage Learning-- on page 285:I paraphrased Andrews' lists for the beep codes when POST test fails:
One beep followed by three, four or five beeps-- means motherboard defective; replace motherboard
Two beeps- can be various problems and might list an error code on screen, write down the error and google search it for specifics.
Two beeps followed by three, four or five beeps-- RAM defective --replace RAM module(s)
Three beeps followed by three, four or five beeps-- keyboard or monitor ports on motherboard is bad; replace motherboard or use expansion cards for adding USB ports for keyboard and a graphics card.
Four beeps followed by two, three or four beeps-- serial port or system timer is bad, motherboard is defective and needs to be replaced
Continuous beeping -- bad power supply; replace power supply
Siren Sound -- the CPU (processor) has overheated
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References
Andrews, J. (2010). Supporting Processors. In A guide to managing and maintaining
your PC (7th ed., p. 285). Australia: Course Technology.
