Why did the PC stop turning on after replacing the cooler on the processor?

Question

Processors

The cooler was very noisy, I decided to replace it. I changed the thermal paste, cleaned the computer, while doing all this I took off the video card and the RAM bar (it had to be put in the second connector, because the new cooler prevented it from being put into the first one). I installed everything, the PC starts up, everything spins, glows, but the image is not displayed on the screen.

checked the usb ports by connecting the mobile to them, the charge is on

Answer 1

You need to take an eraser and gently rub the contacts of the memory bar on both sides (do not forget to brush off the rest of the eraser afterwards).

Answer 2

lost contact somewhere. Most likely in the operating room. Move and pull whatever you can get.