So my friend was having some problems with his PC, and he has been for a while. Most notably his computer seems to be having some sort of problem with his RAM usage, showing like 86% memory usage with only about 4 gigs being used when he has 8 gigs of RAM. He also had an issue with the headphone jack on his case not working so I agreed to look inside his case for any obvious issues like a loose connection or something.
So we open the case up, lay it down on its side, I pull out my anti-static wristband and attach it to a metal part of the case. The cables connecting the case ports look fine, so we never did figure out what was wrong with them. Then I decided to reseat his RAM in the hopes of maybe fixing his RAM problem. I took both sticks out and switched their positions, and I THOUGHT that I properly inserted them, I heard and felt a click when I was pressing both back into the motherboard. We put the panel back on and wire everything back up. Then comes the worst nightmare for someone in my position: his computer boots, doesn't output a signal to his monitor, and then shuts off after about 20 seconds and then restarts... over and over, not outputting a signal I switched the RAM back to their original position and hoped for the best, but nope, nothing.
All fans were running (GPU/CPU), the motherboard has some built-in LEDs that were lighting up, and everything seemed alright on the surface. It seems like a motherboard issue but I honestly don't know. I'm not an expert, just a guy who builds computers for fun every now and then.
I should mention, he's had this computer for about 3 years, he bought it prebuilt from IBP. It's been running no problem since then besides the RAM and headphone jack issue.