how to fix Desktop Computer shuts down after few minutes.

Having problem with your old desktop computer?Some common problem in desktop computers is shutting down for few minutes. If your computer is also having problem like this. then this topic is for you. I found out that every time i play a game on my old desktop computer my computer shuts off. I found out that if it is 3d games like for example counter strike my computer shuts off.  I also found out that 3d games consumes more power for the video card more power for the processor of the computer that causes the problem. It heats up the computers processor. So my friend said that i have to open the computer and apply more thermal compound to the processor. so i open up my computer  .and apply thermal paste on the processor just lije the picture above.then my computer works fine as of now.The reason is that the processor and videocard eats up more power, more power the more heat gained.