BSOD Possible motherboard failiure / power supply?

Hi, ! for almost 2 years now I've been having trouble with my Custom build computer!, I'll link the specs In the end so don't worry.
however, I've been getting like 20 Different Bluescreen Messages the last year....
at one point I had to reinstall windows every third day ("NOT JOKING!!!")
I've almost replaced every (original) part in my computer..
The last couple of days I've been getting Bad_pool_header
and before that
IRQL_NOT_LESS_OR_EQUAL
DATA_BUS_ERROR (almost sure of)
PAGE_FAULT_IN_NONPAGED_AREA
KERNEL_DATA_INPAGE_ERROR
BAD_POOL_CALLER
memory_management
and yeah u get the point....
Could this be caused of..
there, I'm back in normal font.
anyways. What could be the reason for all this ! :O even tho I have almost replaced every part in my computer!
I can access BIOS so I don't think it's the bios.

Things that I've replaced.
HDD,
GPU
CPU
MOUSE ( cuz it kept on disconnecting and reconnecting) only on my computer tho.. but i found out what was the problem on my 3rd mouse.. ( havn't been very patient because You arnt really in the mood for that kind of stuff when everything keeps on crashing when you put alot of money into a computer! you want it to work.
DVD+RW/CD player.
RAM

___________________________________
now on to the specs. ( not 100% correct )
AMD Athlon II X3 425 AM3 Dual Core, Socket AM3, 2,7GHz, 1,5MB, 95w, Boxed
And DDR2 RAM memory 4gb (got it as a birthday gift (I was 16)
GPU: ATI HD 5750 (and it requiers 450W) 1gb GDDR3
Western digital 320gb
DVD burner.. just some random.
ATX power supply 500W
ASUS M4N78 PRO, Socket-AM2+/AM3 1ST GeForce 8300, ATX, DDR2, GbLAN, PCI-Ex(2.0)x16

I can probablly figure out by now that it is the Motherboard which i havnt changed... Is there any BIOS setting that could cause this. havnt been trying to flash it. EDIT: or the power supply since I dont think i've got enough power.


as it is for now I'm getting an error in windows installation when extracting files (w7 ultimate) 0x80070570 no one seems to have found the sollution.
and I cant try my ram since i havnt got windows installed (if im properally informed) I'm downloading it to a USB stick and Will run it from there later this afternoon. but I think that the BSOD will come back eventually as it always does.


Well, The BSOD went away when I changed my HDD this autmn. but now recently i've been experience LOADS of BSOD's with Different errors... I'm ****in about to cry now since I've changed everything in this computer !!! EXCEPT THE THING THAT SEEMS TO BE THE PROBLEM which is the power supply and Motherboard!!! Going crazy! please help any awEsome tech guy!

but due to the fact that I was experiencing these errors before I changed to such a Demanding power guzzling graphic card.even then when the power supply was enough... So confused!

Or. it could be that I've Fixed the HDD which was the originally problem and then I got my new graphic card. which perhaps would cause this new serie of bluescreens.

(If u don't understand my speculations or my bad english please just TRY to read between the lines)