PC crashes when playing games.
I've been playing Left 4 Dead 2 perfectly fine since May to June. Then went for a vacation for two months. When I came back, the computer (desktop)is still working fine. So NO problems with the computer's fan and other components overheating (Steam support and other forums mentioned this as one of the possibilities of the problem). Also, Symantec AV software has been installed also before I got Steam and the game. I am mentioning this because I've been to Steam support and other forums saying that Symantec and other AV software could make the coumputer crash. Since I've been playing it with the AV activated, I do not suppose that this is the problem, unless you prove to me otherwise.
I've had this problem since my little brother arrived from his friend's house (he stayed at his friend's house for 5 days). I was able to play Left 4 Dead 2 for many hours until he used the computer. After he used it, the computer started to crash whenever I play Left 4 Dead and other games like Heroes of Newearth. However, it does not seem to crash whenever we play Counter-Strike 1.6. Another mysterious event that took place was two days ago. I've been trying to fix it on my own by re-installing Steam and Left 4 Dead 2. To my suprise, it did not crash after 3-5mins after playing the game. I played the game offline when it worked. I completely closed uTorrent when I played it online using Steam. It did not crash. At least two days ago. When I tried doing the same procedure today, however, it did not work.
My brother who is graduating in IT said that I should check if there are any malwares. I checked and quaratined them. But he said the damages could be irreversible. If so, how did the game work and not make the computer crash two days ago?
So anyone here who could help me? I would really appreciate it if you can give me the time and patience. I am trying to fix this as soon as possible because my copy of Dead Island is on its way.