Greetings, now I will try to explain to you how and in what cases you should independently examine the system unit of the computer and find the cause of the breakdown if you do not have technical knowledge.
Most often they address me with a problem on the video card. If you turn on the PC and your monitor is off, then first you need to check it. Try connecting the monitor to another PC. If the image does not appear on the screen, there you should check the connection cable, it may be damaged. Try connecting the monitor using a different cable. If this does not help, then it is not a monitor.
Make sure that the computer starts when you turn it on. This can be determined by ear. If this does not happen, then move on.
Sometimes it happens that the power supply fails or lacks power. To verify this, you will need to install another power supply. Try to ask friends, this is an inexpensive thing, usually everything is easy to give for verification. Getting the power supply from the computer is quite simple, usually you just need to unscrew 3-4 bolts and disconnect it from the motherboard. A new one can be installed in exactly the same way, but it is not necessary to screw it on. If the problem remains, then move on.
Carefully disconnect the video card from the motherboard and connect it to another computer - this is the easiest way to check the operation of the video card. If the video card works, it means that it is working. But it will be useful to do an additional health check.
I can advise you on several programs that will do this: FurMark, OCCT, 3D Mark. Look on the Internet, there is an instruction for each of them.
If there is still no image after the previous paragraph, then most likely the capacitors swelled on the video card. Inspect them very carefully and make sure they are normal. If at least one swollen capacitor is found, the problem is probably in it. In this case, the video card must be carried to a service center for repair.
(Capacitors are usually similar to jars, they stand out against the general background of other parts of the video card)
If you cleaned your PC yourself and removed the processor from it, then most likely when you installed it back you damaged the socket. In this case, you must contact the service center for repair.
It is possible that the video card does not work due to a malfunction of the motherboard (damaged north or south bridge, swollen capacitors). It will not work on its own to verify the efficiency of the bridges, but you can always inspect the capacitors yourself (see paragraph 5).
Hello, my name is Timofey, I live in the Republic of Belarus (Gomel). I graduated from the Gomel Technical University named after P.O. Sukhoi, with a degree in engineering. I earn a living by repairing computers, laptops, phones, tablets and other gadgets.
I am interested in video games (post-apocalypse genre), I read books (popular science literature), study history (mainly Latin America).
For some time I taught physics and mathematics at school, and also taught home appliances repair courses.