Computer stuck at loading operating system

[nator344]

Hello, started having problem like a week ago where my computer started laggin really bad, couldnt even move mouse without major lag. Anyways so i got sick of it and reinstalled windows 7 64 bit, now my computer gets stuck at loading operating system. Thought it was SSD so took it out and put in a 500gp wd hard drive (I know it works fine, becuase had it run on company server all week before i used it) so then i installed it on their and still was stuck so then i took out my other 500gb wd hard drive where i store all my files, just so i could make sure that my OS can only install on one item and not be corrupted by any other drives. So now the problem still presit and i have tried resetting my bios by taking out battery for 10 min, still no results, so then i ran startup repair (Had no hope) and it still didnt work. Need help and bellow I will post all my hardware, by the way my computer is a custom build and has been working fine for 2-3 months. Also I do overclock, but i doubt that had anything to do with it, because it started to lag weeks after i started overclocking.

Ok so heres my hardware:

HDD: WD 500gb x2 or Intel SSD 320 Series 80gb 3gb/s

Motherboard: Gigabyte 990fxa-ud5

CPU: Amd fx 8150 black edition 8 core processor

RAM: Corsair Vengeance ddr3 16gb

VGA: HIS ice qx radeon hd6950

Power Supply: 1000w kingwin gold

and i have a custom water cooling system and optical drives work fine
Motherboard:

 

[Dark Lord of Tech]

Have you looked into a possible ram module issue?

 

[nator344]

So do you think i should try just running 8gb of ram