No Power to Motherboard

[question]

My pc was work normally before I shutdown it,I havent change anything of the setup,add/remove any device.
My pc cannot switch on when I press the power button.
I have try to change another Power supply,but it no work.

For the previous power supply, the fan at motherboard can run for a while less than 15seconds. then off. I could see the Led is lighted. I have try to remove all the ram,hard disk, network card, floppy dish....still same.

If I use another power supply(ok condition),the fan never run at all....

I have checked that the capasitors....were ok,no lead...

[NooNoo]

Have you checked that the connections from the motherboard to the switch are correct and seated properly?

What motherboard make and model and what processor do you have?

[PBase001]

No beeps during startup?

How about the power light does it flash or come up in a different color other than green?

What brand and model is the computer?

I would be looking to get a replacement motherboard from the manufacturer if it's still under warranty.

[Guts3d]

Also, the case power switch itself may be stuck on, or not connecting at all.

[slgrieb]

Question, I don't think there's any doubt the mainboard is dead.