Computer won't boot-up

hi, is the ide-ata enabled in the bios? do you have sata? and is it enabled?also did you put thermal compound on the cpu' s heatsink when you put it back on the cpu? the 2 second on thing sounds like over-heating,do check the bios first. alot of motherboards have a thermal shutdown, so if the fan or compound failed, it would quikly shut off. as for the channels not working-you can try your primary drive, and see if it boots. but first see if it is on in the bios. check and replace the battery on the motherboard. post again if you need help good luck! hope this is helpful.