ok, This is a friend of mine and his emachine wont boot. I said I can take a look at it real quick and give him my *expert* opinion.

I got it, plugged it in and it immediatly turned on. nothing. the fans come on and the hard drive spins up after about 30 seconds but nothing.

I swapped PSU. the new (bigger)PSU wont turn nothing on(not even the fans).
I tested each PSU with a 75 Watt load and they both work.
I put old PSU back in it and same thing, fans turn on but nothing.
I pulled all IDE cables and Power connectors and floppy.
same thing, fans only.
yanked ram, same thing, fans only.
so now, the only thing plugged in is the mobo.
fans only, no beeps.
I cleared cmos, nothing.
I think its a bad motherboard.

oh, just a quick follow up,
I yanked all PCI cards. the graphics card is built in.
still same thing.
the only thing plugged in is the CPU.

That other power supply you put in might have fried everything if im correct in stating ( someone prove me wrong if I am. ) Emachines use speical power supplices for their motherboars and a standard PSU could blow up everything in theory.

well lets hope that it was already messed up before that.
When I put the old PSU in, it still does what it always did.

I checked the power connector to the mobo and there is 2 wires that appear to be added from the normal PSU. they are tied into 2 reg wires. Thats prolly why it wont turn on with the new PSU.
so what could it be?????????????//

I read a # of posts on here and none of them indicate that there is a "special" PSU on them.
so I still think its the Mobo.