hello, i am getting semi-random blue screen errors which is possibly caused by my graphics card.

my system is:

amd phenom ii x6 1055t be

powercolor ati radeon hd 6950 1gb

western digital wd1002faex-00y9a0 (which i looked up from hard disk sentinel)

2x4 gb 1600 mhz gigabyte rams (not sure about the exact model name)

thermaltake 450W power supply

there are some exact situations about when this error happens:

in lobby of a game (dota2, bloodline champions etc.) specially when i alt+tab

while loading a game (cod series' loading screens between each mission, loading a skyrim save etc.)

or surfing on internet

and there are some different situations when the error happens:

a screen like this (http://i45.tinypic.com/nq5owz.jpg , colors vary) or pure black screen appears and anything works on computer except the restart button, yet i can hear voice chat and songs i play via winamp or any other media and doesn't restart itself

a dark colored screen appears and there is a very loud sound afterwards and computer restarts itself, gives me the error i copied at bottom

this error NEVER happened before i inserted my graphics card to the computer and i tried the regular driver from original DVD and latest versions, didn't make a difference

Problem signature:
  Problem Event Name:    BlueScreen
  OS Version:    6.1.7601.2.1.0.768.3
  Locale ID:    1055

Additional information about the problem:
  BCCode:    124
  BCP1:    0000000000000000
  BCP2:    FFFFFA800842F498
  BCP3:    0000000000000000
  BCP4:    0000000000000000
  OS Version:    6_1_7601
  Service Pack:    1_0
  Product:    768_1

Files that help describe the problem:
  C:\Windows\Minidump\122912-15506-01.dmp
  C:\Users\Nedim\AppData\Local\Temp\WER-35303-0.sysdata.xml

Read our privacy statement online:
  http://go.microsoft.com/fwlink/?linkid=104288&clcid=0x0409

If the online privacy statement is not available, please read our privacy statement offline:
  C:\Windows\system32\en-US\erofflps.txt

your PSU is probably choking on the load, I use Corsair and the TX650 would do wonders for your rig long term

Corsair Carbide 300R, TX850V2, Asus M5A99FX PRO R2.0, Phenom II 965 C3 BE, G.SKILL RipjawsX DDR3-2133 8 GB, GTX 260 SLI, Asus PA238QR, Windows 7 x64 Enterprise

Asus M4A77D, Athlon64 X2 4200+, DDR2-800 6 GB, HD 5450, cheap 450W, Server 2012

first of all, are you sure? because when i bought my system the shop told me that the supply can handle this computer.

also there's an odd thing that it also appears on game lobbies i mean psu isn't even going for a hard time there

is there a way to find out if supply is insufficent for my system?

thanks for the response