I reread your whole thread again in case I missed something and note a couple of things. This issue started when you were using Windows 7 where at one point a friend replaced the gpu. The issues you describe that the machine will crash after a short period of time playing games can be caused by a number of things one of which can be an under powered PSU or power supply. I did ask at one point what make and model you were using but you were unable to access the case or something. We need that information so as soon as you can find out the better.. Oh and please post the new dump files.