Then it's time to open the case, check all fans (especially the one on the graphic card) and the heat paste. it's not software, most likely, it's hardware.
First off, hello and thanks for taking the time to read my post and help me out with my issue!
So a few weeks ago (I think) I got home, grabbed my laptop, booted it up, and the screen kinda freaked out for a quick sec and went back to normal (might have been due to how I grabbed it which is probably the source of most of the trouble I'll list). When I finished loading up and tried using applications, that application would freeze and give me the "Not Responding" bull-crap after showing no signs of response for 2-3 minutes. This was for every single thing I tried to do and would sometimes start giving me a message saying that Windows is not responding and gave me two options: stop it or cancel.
However, that issue got resolved. I got my computer wiped and installed Windows 7 Ultimate. The freezing stopped and everything was back to normal after updating a few drivers until I booted up a game. The first one I did load up was League of Legends. After a few minutes, my whole computer shut down and I found out that it was because my computer overheated. Keep in mind that this was a game that my computer had no problem playing and would never make my comp crash due to temperature problems. I tried other games (such as metal gear rising and dark souls) and the result was pretty much the same.
So basically, my laptop ran into an originally very bad but easily solved problem but upon being fixed was not able to cool itself sufficiently enough while playing games that it had no problem running before. I've even installed programs like SpeedFan to see if the fans weren't running but they are (although I'm not sure if they're running as well as they were before). I'm currently going to try and purchase a cooling pad to see if that will alleviate the problem but I still want to see if there are any other issues or another solution.
Specs + Model:
Model: Toshiba Satellite P755-S5398
OS: Windows 7 Ultimate 64-Bit
Intel Core i5-2430M CPU 2.4 GHz
6 gigs of memory
NVIDIA GeForce GT 540M