Need help, hardware being a b*tch

i have this PC made intirely out if second hand parts, and styff i have found. i am trying to find out what is wroung with it.
i have been forced to reinstall windows a couple of times becuse it just keept getting the blue screen of death. but when i try and install windows (vista 32bit, i dont think it can handle anything newer) from my bootable usb stick the time it takes to load the UI and go throught the steps, takes for ever (a couple of minutes to do simple things), what inthe system is it that can cause this problem?

also i have noticed that 3 times now, after i have installed windows and some of the drivers, which it does fine. i then procede to unstall the drivers for my gpu, and after i restart i always get the blue screen of death right before the login screen. WHY? i ask you

the hardware in the system is as follows:

antec true550P EPS12V PSU (almost 100% sure that there is nothing wrong with this part)

abit i-N73V motherboard (motherboard CPU and RAM all came from the same computer and was assembled when i found it

core 2 duo processor

2 GB kingston DDR2 800Mhz RAM 1 stick

500GB hitachi Harddrive (there is nothing wrong with this harddrive) 

ati Radeon 3870x2 GPU ( this graphic card also work perfectly, however i am not sure if any of the parts is compatible with the otherparts)

 

i have tried running memtest, and i got no errors.

 

Any help?

BSOD randomly means it's probably GPU hardware failure...Try installing different drivers for your graphics card.

but its not random, it happens right before login screen each time... i just reinstalled AGAIN, and i got a BSOD in the setup

 

hmm.. I used to run into a similar issue but mine had to do with drivers. I would try out different drivers I guess