Unexpected shutdowns while gaming

So i don't even know where to begin I have HP DV7-6143cl for almost 3 years never had an issue. But after like 1 year my stock HDD died and i replaced with another one, whitch nearly died as well. Now i have one HDD and SSD in my laptop. All problems started after the first hdd died so there is a problem. When i'm trying to play any game like War Thunder or Sacred 3 my laptop shutsdown after few minutes of playing. For example when i play War Thunder i chooce the lowest graphics then laptop won't crash for an hour or so. When i bought this laptop i could play any game without an issue with best graphics. One more thing i noticed that i get very low fps when playing java games like Runescape, or even Counter Strike 1.6. I just don't know what is wrong. Maybe power supply is broken, gpu overheat or just bad video drivers. All i tried is not working. Anyone experienced something similar?