Replaced Logic Board, RAM, and hard drive connecting wire, but Macbook Pro 15' (Mid 2010) now freezes and shuts down randomly

I have a mid 2010, Macbook Pro '15. Summer of 2012, it kept shutting down and making the three beeping noises, so I took it in for repair. I was told that my Logicboard needed to be replaced, so I replaced it, and took my Macbook abroad with me. Halfway through the summer, the three beeping noises resumed, and since I was abroad, I couldn't use my 90 day warranty and take it back for repair. By the time I returned to the US, my warranty ended, and I was told that the RAM actually needed to be replaced. So I replaced that.

In May of this year, my laptop wouldn't start and instead showed a folder with a question mark. I took it to repair and was told it was the hard drive wire that needed to be replaced, so I replaced that. Less than two weeks after, my Mac began freezing whenever I had a YouTube video or song playing- it made short, staticky sounds and then shut down. Now, it shuts down randomly even when I'm not playing videos or songs, and regardless of if it is running on battery or plugged in. Since I got my hard drive wire replaced, I've also noticed that the laptop takes an incredibly slow time to start up.

The last the Genius Bar technicians looked at my computer when replacing the harddrive wire, they hadn't said anything else was wrong with my laptop.

I've spent almost $1000 total fixing my macbook and am quite sick of going through this over and over again. Can anyone help me know what went wrong this time? (I have no apple care) Thank you in advance.