Failure to understand the nature of certain computer problems often leads to errors in diagnostics, without which qualified repairs are impossible. And you should approach the search for a problem from its exact description. A malfunction that is described by the words: “when you press the power button (power), the computer does not turn on, but the fans work” is called the absence or initialization error. It should not be confused with "not turning on" - complete inactivity on pressing power, since the causes of these two problems are usually different.

Initialization, in this case, is the readiness of the equipment for operation. And if any of the devices critical for starting a PC refuses to start, we will observe a characteristic picture:

  • after turning on the system unit, a loud noise of the fans is heard (they rotate at a constant high speed);
  • the keyboard and power indicators light up and do not go out;
  • the screen remains black.

Nothing else happens.

The reasons

According to statistics, the most common source of such a problem is the following:

  • damage to the BIOS - a program stored in the CMOS flash memory chip on the motherboard responsible for booting the PC, as well as for checking and coordinating the operation of all its devices at the start stage;
  • a failed processor or a malfunction of its power supply system;
  • inoperability of RAM (RAM) or incompatibility of installed RAM strips with each other;
  • malfunction of the system logic chips (chipset) on the motherboard, especially often the north bridge.

Other reasons that can also give such a “clinic” include damage to the elements of the motherboard, leading to destabilization of the power supply of devices, a defect in the solder contacts of microcircuits, a power supply with a “drawdown” of voltage along individual lines, a dead CMOS battery, and other problems equipment installed on the PC. However, this is less common.

It is also important to understand that this problem is never the result of software failures in the operating system. Because it won't even start downloading.

Diagnostics

What can the user do in such a situation? Even without special equipment, you can try to solve the problem at home. It is enough to know how to use a screwdriver.

Reset BIOS settings to factory settings

This is the easiest and, at times, very effective way to troubleshoot computer boot problems. If your case is not the most difficult, perhaps it will help.

  • turn off the computer power and remove the system unit cover.
  • Locate the coin cell battery on the motherboard and remove it from the socket.
  • close the contacts of the battery socket with each other, for example, with a screwdriver;
  • reinstall the battery.

There is another option to reset the BIOS - a jumper (jumper) Clear CMOS. It must be removed and for 15 - 20 seconds. and move to two adjacent contacts, then return to its place. Sometimes the jumper is called differently: CL_CMOS, CCMOS, CLRTC, CRTC, etc.

After doing these operations, connect the power to the computer and try to turn it on. If the problem is fixed, its cause lay in the incorrect BIOS Setup configuration.

Turning off all unnecessary

If the first method did not help, move on. Let's try to exclude the influence of equipment that is not necessary for a successful PC start. To do this, you need to prepare a table covered with insulating material (polyethylene, rubber, plastic, wood, etc.) on which you will assemble the stand.

Let's get started:

  • power off the PC and remove the case cover;
  • remove the expansion cards from the motherboard slots, disconnect the power wires and interface cables from it, remove the memory strips;
  • remove the motherboard from the case, put it on the table and inspect for artifacts - swollen capacitors, overheating traces (darkening and deformation of plastic parts), mechanical damage and other defects;
  • if there are no artifacts, install one memory bar in the slot, connect a video card (if there is no built-in one), a monitor, a previously removed bootable hard drive and a power supply;
  • turn on the power supply to the mains;
  • close the contacts of the power button with a screwdriver - Power Switch (can be signed as ON, PWR_ON, PC_ON) - this action is similar to turning on the computer by pressing this button.

If you see the operating system loading on the monitor, then one of the disconnected devices is causing the failure. Well, if nothing happens except for the rotation of the fans, let's try to figure it out in more detail.

  • Start the system. Gently touch the processor heat sink and large board components - chips, mosfets, etc. with your hands - they should normally be warm. Strong heating (do not burn yourself!) - indicates a malfunction of the elements (soldering defect, short circuit), and the complete absence of heating (room temperature) indicates, most likely, that the node does not receive supply voltage.
  • Power off your PC. Remove the memory bar, remove the oxide layer on its contacts by rubbing with a school eraser, blow through the slot where it was, and install it back. Turn on your computer. If the problem is solved, the reason was in poor contact between the RAM and the board connector. If you don’t dare, install the bar in another slot - perhaps he is to blame.

Replace parts with known good parts

None of the methods helped? The last thing that can be done at home is to replace PC devices in turn with working ones, of course, compatible with your system. However, there is a risk of damaging them.

If there is no such possibility or desire, as well as if the described problem occurs on the laptop, the only remaining option is to contact the service center.