Hi all, I want to keep this short but i need some advice as to where and how i can find out what the problem is with my PC Only a few days ago whenever i do anything demanding (i.e. rendering with a 3D program or even virus scanning with Norton 360) my pc just shuts down unexpectedly ! General internet viewing and video/music playing etc it fine so i am guessing its a cpu thing ? i did a little googling and i have since ran memtest and a program called Prime64 to which i left running 24/7 for 2 days on torture test and pc was fine ? I am on W7 64 all upto date etc so i need to know how to test things further, i.e PSU, CPU, Graphics or what ever else is needed. I am a little green with the jargon so if any help is offered please be basic with me lol Thanks in advance for any input, it will be greatly appreciated. Kindest regards, Vale.