u need to change MB, look at the dfi x48 t3r or asus p5e3 something, gigabyte is bad

then change your ram, im rather sure that that isnt micron bassed

3rd change the psu that thing is trash, look to a corsair 750TX or pc power and cooling 750\

4th u need to swap the HDD look at a 640GB WD or a 320GB 7200.11 or 1TB samsung, dont waist money on a slow 500GB drive from the worst maker, if u want a 500 go samsung f1