Windows 7: Winrar issues a lot of CRC errors

Ok so this is really starting to annoy me, everytime I download something, lets say the Battlefield Bad Company 2 patch v602574 (2,4GB) and when I try to extract it using winrar(I have also tried 7-zip ) it tells me that the files 25, 29 and 31 etc are corrupted, and when I try to download it again, it happens again, only with different files. And this happens on everything I download.



So I was hoping someone had an idea on what it could be? I've been reading around on other forums, and they said it could be the RAM, but I've tried memtest and it passed.

I've had some BSOD on this system (it's only 4 days old) but after setting the DRAM voltage from 1,5V to 1,6V I haven't had any problems with BSOD.

Current system:
AMD Phenom II X4 980
16GB of Corsair XMS3 DDR3 1333MHz CL9 RAM x4
PowerColor Radeon HD 6950 2GB x2
ASUS Crosshair IV Formula
And one 1TB HDD and one 640GB HDD with Windows 7 Ultimate x64