Can't Install Windows 7 When Enable 4 Cores?

I build my pc about 6 month ago, My PC specification:[CODE]fter one month my windows start showing BSOD every week once, i thought it's a software problem, but about two weeks my pc start to be very slow and keep crashing even if i browsing internet the internet browser crashed, so i decide to format my hard disk and install windows 7, when i boot from windows dvd and format my hard disk and start copying files after finish copying files it's show BSOD and restart my pc i thought from ram or hard disk, but i searched in the internet and i founded that i should try to make your cpu work with one core, so i changed it to one core, I installed the windows and everything fine but when i changed it back to 4 cores the problem back.