power problem

[goldenjaguar]

i have intel915 gav, 80gb samsung sata hdd , 512 ddr ram,dvdwriter,cdwriter , APC back ups .When i swithch on the supply my system doesnot starts ,this problem had occured earlier and i changedmy board thrice and also my smps twice but the problem continues sometimes it comes to normal state after 2 or 3 days please help me

[Tech Geek]

maybe loose connection