I am in big trouble now. I have being using a pc for quite long time abt 3 to 4 year now. Now all of a sudden when I am playing the comp my monitor goes blank. And the cpu led changes from yellow to red. I though it might be on standby mode I checked but it doesn't work. I cant shutdown the cpu by holding the power button and I cant reset it. If I want my computer to start again I am having to remove my power cable the again plug it in. and the again the comp starts but after sometime the same things happen. I dont whether its software or hardware problem. So can anyone tell me wats happening

Possible over heating.

Check all fans are working, and clean.

They get very dirty after a few years, and this can lead to failure.

thanks