Question : Problem: emachine t2672 won't power up

When you power on, the fans  begin a few seconds later, and then 2-3 seconds later, they stop spinning and machine does not start.  Also does any one know which pins the power switch, hd led and pwr led are supposed to be placed.

Answer : Problem: emachine t2672 won't power up

Have you reseated the ram or checked the heatsink is firmly attached to the CPU. You may want to remove the heatsink an clean the thermal paste off and reapply new thermal paste as this may be an overheating issue.(you cannot use the old thermal pad/paste once it is removed from the CPU)
Emachines are famous for PSU's and motherboards dying at the same time.
I would try a power supply replacement first.
If the replacement of the power supply doesn't change anything, then at this point it would be prudent to remove any extra cards and drives or peripherals other than the CPU, ram ,and video card, and see if it starts. If it does then one of the components that was removed may be the culprit. Addidng them back into the PC one at a time and restarting each time, may show which component is bad.
If none of this works then you are most likely a candidate for the Emachine PSU motherboard replacement.
Does this look like your motherboard?
http://www.e4allupgraders.info/dir1/motherboards/socketa/au31.shtml

Here is a link to the manual for this motherboard as it should have the pinouts. http://www.e4allupgraders.info/dir3/files/manuals/AU31_manual.zip