Everything is plugged right, I just unplug it and then plugged it back wth ?Double-check both your 24-pin and 4 and/or 8-pin power connections from the PSU to the motherboard. Also, same for PCIe power connections to your GPU (assuming you are using such a config).
Everything is like before, didn't change anything, and anyways at the first boot the pc turned on for 3 secs and kept restarting, then I disconnected the power cord and then here we go, black screen.Is your display/monitor connected directly to your GPU or to a video port attached to your motherboard?
Omg, I cant tell how to thank you, one of ram slots we half connected and now everything's fine, again thank you.Disconnect power from the system. Then press the power button to discharge any residual power in the system.
Then, remove your memory and re-insert. Make sure memory is fully locked into the slots.
Try powering up again. Memory often gets dislodged slightly when messing with the motherboard power connectors, especially the 24-pin one.