The computer does not start, the fans are spinning, the screen is black, and the system speaker beeps or is silent - in 80% of cases this is not a “burnt-out processor”, but a predictable failure at the POST stage: power supply, RAM, video card or motherboard. Correct decoding of BIOS sound signals and understanding of the self-testing logic allow you to quickly distinguish RAM/GPU problems from CPU/motherboard defects and timely transfer the equipment for professional computer or laptop repair to the TEND service center in Kyiv.
What is POST and why is the computer silent
When the user presses the power button, the power supply supplies voltage, but the operating system does not even think about loading yet - the built-in BIOS/UEFI POST (Power‑On Self Test) is triggered first. At this stage, the motherboard sequentially checks the power supply, processor, RAM, video system, basic controllers, and only after successful completion of POST transfers control to the bootloader.
If the computer does not start normally, you see a black computer screen without a logo, and short or long beeps are heard from the system speaker - these are BIOS error codes, by which you can understand where exactly the board “fell”. In a typical scenario for an office system unit in Kyiv, the sequence is as follows: first, the power lines and the Power Good signal are checked, then the CPU and chipset are initialized, then the RAM is tested, only after that the video output and interface are launched, and only finally the BIOS transfers control to the disk.
If something goes wrong at any of these stages, the computer beeps when turned on with a certain combination of signals or is completely silent. That is why, in high-quality diagnostics, computer repair at the TEND service center begins with an analysis of the behavior of the PC at startup: how the fans behave, is there any sound, does the power go out, do at least one-time “beeps” appear when the RAM is removed, etc.
Deciphering BIOS sound codes
Different BIOS manufacturers (AMI, Award, Phoenix, Dell) have different sets of codes, but the logic is the same:
-
short series of signals more often indicate problems with RAM or video card;
-
unusual continuous or “floating” squeak - indicates overheating or power supply;
-
complete silence with a working speaker - a failure before the audio channel is initialized (a deep problem with the motherboard/CPU).
Main AMI BIOS codes
-
1 short signal - POST was successful, the configuration of the underlying hardware is normal. In this case, it makes sense to look for a problem at the disk, system or driver level, and not immediately go into computer repair.
-
2 short beeps—RAM parity error. Usually solved by rearranging
