Lenovo Legion Y520 crashing non-stop

Basically, this "wonderful" laptop that has been recusitated about 4 times is reaching its end. The main problem it had been having for a while was freezing, requiring me to cold shut down or freezing and giving me the blue screen of death. I have already completely wiped it and now it has been mainly just freezing requiring me to cold shut down. I normally launch gta 5 and while playing it freezes almost instantly. About at the start of this year I took the laptop apart and completely cleaned it and about a year and a half ago I had replaced the thermal paste inside the laptop. I will be replacing the thermal paste this week and cleaning it again even though the air vent where heat is emitted doesn't give off too much heat (back when the computer was very dirty the heat would be able to burn my finger a little). Due to this I highly doubt the thermal paste and heat distribution is the problem. If anybody has any idea what the possible problem can be or has experiences similar issues, let me know what to do. I have an option to buy a desktop and throw this laptop away but I was supposed to receieve it as a gift at the end of this year and would have to dip into my own money to get on right now.