getting random shutdowns when system under load

[george the lemon]

so my pc keeps randomly shutting down every time the thing comes under load i ran some gpu benchmarks and i think it might be this as my pc passed memtest aida64 cpu stress test and the psu is brand new but sometimes the pc will fail the test

 

my gpu is a ati hd5450 i know its not a gaming card but could handle some games fine a few days before.it also comes up with this whenever i restart 

 

Problem signature:

  Problem Event Name: BlueScreen

  OS Version: 6.1.7601.2.1.0.256.1

  Locale ID: 2057

 

Additional information about the problem:

  BCCode: 124

  BCP1: 0000000000000000

  BCP2: FFFFFA80054B28F8

  BCP3: 0000000000000000

  BCP4: 0000000000000000

  OS Version: 6_1_7601

  Service Pack: 1_0

  Product: 256_1