How did you confirm it was the CPU?
It might be that the PSU or RAM, or even motherboard, is at fault. How old is the PSU, and what make and model is it (should be shown on a sticker)? Also, have you tried with only one stick of RAM at a time in each individual memory slot.
Im pretty certain it was the cpu because it even small burned part on its underside and also when my friend tired his i3 2100 in mine and it worked.. weirdly.. and the psu its a corsair 500w around 3 years old now.. and i will try the RAM thing..