i have a custom built computer that i built about 3 years ago. and it recently just stoped turning on. i bought a new and better psu and it still wont boot?? i am thinking it might be the motherboard. i have tried two different video cards and i know they work. and nothing happens. if you could help me that would be great. the motherboard is a asus and i dont know the model. it has an intel core i5 2500k in it at 3.0GHz i think.