Just in case, I note that only the case is considered here if after clicking the power button on the screen there are no messages from the computer (i.e., you see a black screen without preceding your motherboard inscriptions or a message that there is no signal) .
If you see a message about what some error has occurred, it is no longer "does not turn on," this is not loaded the operating system (or there are some BIOS or UEFI failures). In this case, I recommend to see the next two material: Windows 10 does not start, Windows 7 is launched.
If the computer does not turn on and at the same time begging, I recommend paying attention to the material of the computer beeps when you turn on, which will help find out the cause of the problem.
Why the computer does not turn on - the first step towards clarifying the causes
Someone can say that the proposed below is superfluous, but personal experience speaks about the opposite. If your laptop or computer does not turn on, check the cable connection (not only the plug, stuck in the socket, but also connector connected to the system unit), the performance of the socket itself and other related to the connecting cables (possibly the performance of the cable itself).
Also on most power supplies there are an optional ON-OFF switch (usually detect it can be back at the system unit). Check that it be in the "Included" position ( Important: Do not confuse it with a 127-220 volts switch, usually red and inaccessible for simple shift with your finger, see the photo below).
If shortly before the problem appear, you cleaned a computer from dust or installed new equipment, and the computer does not turn on "at all", i.e. There is no noise of fans, no light indicator lights, check the power supply connection to connectors on the motherboard, as well as connecting the front panel connector of the system unit (see how to connect the front panel of the system unit to the motherboard).
If when you turn on the computer noise, but the monitor does not turn on
One of the most common cases. Some mistakenly believe that if the computer is buzzing, the coolers work, the LEDs ("light bulbs") on the system unit and the keyboard (mice) are glow, then the problem is not in the PC, but simply does not turn on the computer monitor. In fact, most often it talks about problems with a computer power supply, with RAM or motherboard.
In general, (for a regular user who has no additional power supplies, motherboards, RAM and voltmeters), you can try to perform the following steps to diagnose the cause of such behavior (before the actions described, turn off the computer from the outlet, and for full de-energization Press and hold the power button for a few seconds):
- Remove the RAM strips, wipe their contacts with a soft rubber eraser, put in place (and it is better to do it on one board by checking the inclusion on each of them).
- If there is a separate output to the monitor on the motherboard (integrated video chip), try disabled (remove) a discrete video card, and the monitor is connected to an integrated one. If after that the computer turned on, try to wipe the contacts of a separate video card and set to the place. If in this case the computer does not turn on again, it does not cook, it is possible in the power supply (if there is a discrete video card, it stopped "cope"), and possibly - in the video card itself.
- Try (also on the computer off) remove the battery from the motherboard and install in place. And if before the problem, you faced the fact that the time is resetting the time - then replacing it at all. (See the time on the computer)
- Please note whether there are no swollen capacitors on the motherboard, which may look like in the image below. If there is - perhaps it has come to repair or replace MP.
Summing up if the computer turns on, the fans work, but no image - most often the case is not in the monitor and not even a video card, "Top 2" reasons: RAM and power supply. On the same topic: the monitor does not turn on when the computer is turned on.
The computer turns on and immediately turns off
If immediately after turning on the computer turns off, without any squeaks, especially if shortly before that it has already turned on not from the first time, then the reason is most likely in the power supply or motherboard (pay attention to paragraphs 2 and 4 from the list above).But sometimes it can talk about the malfunctions of other equipment (for example, video cards, again, pay attention to paragraph 2), problems with cooling the processor (especially if sometimes the computer starts to load, and with the second or third attempt - it turns off immediately after turning on, and Shortly before that, you did not really skillfully change the thermal plaister or cleaned the computer from dust).
Other causes of failure
There are also many unlikely, but still encountered in practice options, among which they were faced with such:
- The computer turns on only if there is a discrete video card, because Inner failed.
- The computer is turned on only if you turn off the printer or scanner connected to it or the scanner (or other USB devices, especially if they have recently appeared).
- The computer does not turn on when the defective keyboard or mouse is connected.
If nothing in the instructions helped you, ask in the comments, having raised how you can describe the situation as it can be described - how it is not included (as it looks like for the user), which happened immediately before that, and whether there were any additional symptoms.