For the past week, my machine with Windows 7 x64 on it is restarting when I am doing something worth, for eg. writing a program for assignments or playing a game. I am still able to watch movies/videos/surf over the internet continually for n-amount of time(without using my keyboard/mouse), but whenever I am trying to do something(sometimes, replying to certain questions on stackexchange) the screen goes blank for a small amount of time, and in less than 3 seconds, the machine restarts.
I first thought it to be over-heating problem(as the temperature has risen here a lot) so I opened the cabinet and cleaned the whole machine. This has increased the stability to some extent. Now I am able to do the aforementioned tasks for a little longer, but even now, I can hear the particular beep sound which hard disk makes when its buffer is lost or the connection interrupted. And then the system restarts.
My only other thought is that the keyboard is having some problem(as I am able to do anything not involving key presses), so I got a different keyboard from a friend of mine. The problem is still there. :(
Any help/comment regarding this problem will be appreciated. I bought ZX 650W power supply quite recently(2/3 months ago) and my graphics card is nVIDIA 9600 GS(which gains a temperature of nearly 52 deg. Celsius while booting)
On running a D7 stress test on machine, and checking the system logs, I found this: