Vista - I cant install any games!!! :(

HEY!

i just reinstalled my PC because i could not install any games on it...i kept getting installing errors on every single ISO file i tried...so i did a clean install of Vista ultimate x64...but the problem is still there....latest ISo file that would not install was BF 2 i got an error on one point of the installation then after reinstall of vista i got the error at another file :S.....i have no idea what it could be...so i really need some help... i think it might be a hardware fail...cuz i get bluescreens sometimes to :O maybe i have wrong drivers or something?? please help

my gear is:

Motherboard: Gigabyte MA790X-DS4

Graphic card: XFX Geforce 260 896 MB Core Edition

RAM: OCZ two blocks of 2GB DDR2 800 (8500)

CPU: AMD Phenom X4 9650 Quad Core

PSU: Aspire Chameleon 550 Watt

OMG...i jsut took one of my RAM blocks out......and now i can install BF2 with no errors at all :O....(OCZ DDR2 Gold XTC 4GB PC2-8500 (2x2GB)....as default my BIOS set them as 800 Mhz and when i try to run them at 1066 Mhz then it wont start :S....what i causing this ???

Hello Nikolaj89,
What is the voltage set to in the Bios ?.
The recommended voltage for your Ram is 1.8V. You may have to up this if you are overclocking to 1066Mhz.
Just be aware that your temps will climb too.
Check in the Bios and see if this is set at 1.8V or set to auto.
The stick of Ram you took out, check to see if it is good, swap it with the other one.
Your Ram can run at 1066Mhz by overclocking it, but the default is 800Mhz.
Hope this helps.