Macbook Pro screen glitches,freezes, & shuts down. Sometimes 3 beeps error arises.

Hello all,

I have a mid 2012 Macbook Pro that I use heavily for college. I recently took it in to my local Apple to have a hard drive cable replaced and since I have received it back I have been having some serious issues with the computer. At random times of use the computers screen will glitch and stay frozen. It sometimes shuts off automatically and then begins to beep 3 times. I have researched that this is a RAM issue but haven't been able to find a resolved answer. If it doesn't shut down on its own then I have to hold the power button down until it shuts off. Sometimes it will restart fine and other times it will randomly boot down or restart in the middle of the restart process. So far I have tried reseating the RAM but that only is a temporary (not even a day) fix.

If anyone has a solution that works for them or any advice in general it would be appreciated. Hopefully I can get this resolved because I cant afford a new one 😕

I have attached some images of some of the screen glitches I get. Note the top image isn't mine, but this is the exact way my screen glitches.