New
#61
First, determine it preciously which parts of your hardware are existing, not new. The cause of the crash should be within it.
Af first, stress test the processor, to make it sure that is is the source of the issues or not.
Hardware - Stress Test With Prime95
And, as it is during gameplay, check the Graphics card, too.
Video Card - Stress Test with Furmark
The new case .... whats about the power supply? If it is inadequate, it may result into a 124 during gameplay.