Energy saving mode?

Question

Computers

Today I cleaned the computer, it is very old and was dusty.
Here I turn on and here the energy-saving mode.
Briefly, how it goes: I turn it on-it takes 10 seconds (nothing works)-and writes energy-saving mode
I tried everything I know, I looked on YouTube, nothing helped
Please help

Answer 1

The signal from the video card is not sent to the monitor, the monitor goes into power-saving mode.
Look for what is not connected, or not, in general, the problem is with the insides: motherboard, CPU, memory, etc.

Answer 2

"Energy saving mode" - this inscription is displayed by the monitor when there is no video signal.
If the cable is connected and connected correctly (for example, a pci-ex video card is connected to it, and not to the built-in motherboard), and the monitor works fine with another computer, then the computer is faulty.
With this level of wording of the question, only carry in the SC.
The problem may be in the banal disappearance of the contact of the RAM or video card, or maybe something knocked out by static (usually users clean the computer with a vacuum cleaner, and they brush directly on the boards with a brush, well, it is killed by static at a time).
In the SC they will check the correctness of the connections of everything inside, and connect the post-card, and it will be visible from it where the plug is. Yes, and it’s not a problem, in principle, to connect known-good components and find out the problem node.
If you don't mind the money, you can try to fix it yourself. There are no superfluous ones - it’s better right away in the SC, until they broke the firewood (already repaired a bunch of motherboards, in which they tried to insert the RAM in the opposite direction, and the tracks burned out; or they put the RAM when the computer was turned off, but in standby mode - the RAM is still powered in it, and you can’t so insert / pull out, and a lot more can happen).