Hi, I am trying to fix my grandchildren's computer, don't laugh... I am 66 and I have fixed my own PCs several times (I enjoy doing this!! ), but now this one got me... it is completely dead, not a sound. I know the power supply is good (I tried it in another computer and is working), the monitor is fine. I have revised every connector, every thing looks to be in order. Is it the motherboard that is dead? :confused:

That sounds about right. Most motherboards have some LEDs that light up on the board, can you see any? If the power supply fans powers up but nothing happens after that then the mobo is at fault.