My computer's fan and custom lights on the case only turn on whats wrong?

I have boughten 3 different power supplies so I know that is not the case. When I came back from a month's vaca. the comp. stopped working. I have tried 3 different power supplies. from 300-500 watts. They only power all the fans inside the CPU (4) and the lights on the case. Initially the computer itself does not start up. All the cables from the power supply are plugged in correctly. This is a custom built computer and it is about 2-3 years old. If all the fans and lights turn on i'm not sure why the computer itself isn't starting up if it is receiving power. Please help!!! I don't know what to do.My computer's fan and custom lights on the case only turn on whats wrong?
If u have a 20 + 4 pin, which u should if ur runnin a P4 board.It could be ur processor has been weak in ur motherboard %26amp; finally went out.If u have another P4 processor change it %26amp; see what it does then.If that dont work u might need to take it in to a computer shop %26amp; let them run a system check on the mother board.My computer's fan and custom lights on the case only turn on whats wrong?
Make sure the front panel wires are properly plugged into the motherboard. Try changing the BIOS battery.
aha try replacing the power switch bet part of it is bad keeping the comp from coming on
It could be that it is not passing POST and there is a hardware conflict. It is getting power because the fans and lights go on, so maybe double check the main power connection and the 4/8 pin connection by the CPU.





Pull all of your expansion cards out (not your video if you don't have onboard video) and use 1 stick of memory and power up. If that does not do anything, pull that 1 stick of memory out so that there is no memory in the slots and see if there are beep codes on start up, then you know that it is getting power, but not passing its tests.





EDIT: Check the 20+4 pin connections and make sure they are secure. It could be a dead processor or a faulty motherboard. If you have another processor for that socket, put it in. If it doesn't work you know it is the motherboard.