Hi, [NAME]-Catchers ,   Just an observation!   Given the age of your PC, is there a possibility that it had a far amount of Dust? It seems to be a possibility that, when you installed the extra RAM, a certain amount of Dust got pushed into the connections - perhaps causing an intermittent connection?
Today when I booted up the PC I got 4 beeps repeating, no display and a flashing yellow on power button. On checking the beep list I see that is a memory issue. I switched off the PC. Pressed and flexed the installed memory and it then booted up. I had installed an extra two sticks of memory on the 10th November bringing it up to 16GB. It was from Crucial. Everything was fine till today. Is it just likely a heat issue that caused the memory to lose connection or just one of those things? I have cleaned out the computer recently and currently the side is off while I do further updates. The computer has not been moved or disturbed since the memory was installed.   
XPS 8300, 4 beeps on bootup