MacBook Pro shuts down randomly while in use/pink screen with lines

I have a MacBook Pro 15” late 2011 with 2.4 GHz Intel Core i7, 4GB 1333 MHz DDR3 memory and Intel HD Graphics 3000 384 MB. It has macOS High Sierra version 10.13.6. I use Firefox as my web browser.

In the last couple of days my laptop has been shutting down randomly regardless if is plugged in or just using the battery.

It freezes unexpectedly, the fan starts to sound really loud and then shuts down. When I turn it back on, the startup screen looks light pink with horizontal lines or it looks distorted with static and then it goes back to normal and it starts up and opens everything that was open before it shut down.

After it shuts down, sometimes when it restarts it shuts down again while loading the start up screen with Apple logo (goes on restart loop). It doesn’t display any error screens or unexpected shutdown message.

I did the PRAM & SMC reset and it still does the same thing. It does this a couple of times a day. The laptop doesn’t feel hot to the touch either. I feel like I’m going crazy trying to figure this out.

Can anyone PLEASE help???

****UPDATE*****

I took my laptop to an Apple Store for diagnosis and they told me that it was the video card starting to have issues and that i needed to get a new logic board since it’s all in one piece.