Inspiron 23 model 5348 wont power up

I have a Inspiron 23 Model 5348 and it just was off one day.  I replace the power supply board with a new one and still absolutely nothing comes on.   The little reset switch with the amber light on it does nothing unless either unless I unplug the little white connector up by the large fan/large copper things.  When I unplug that and push in the reset button the small fan comes on and the amber light comes on but once I plug that back in it all turns off.  Any help...please!!