My Dell 8900 having startup issues, nothing happens when I press Power button. Tried testing the PSU using Built in Self Test button on the back. The light turns solid green and fun is engaged as long as Self Test button is pressed. Also tested using paper clip method, fan is engaged using this method too. I am thinking PSU doesn't seem to be the problem. I am afraid its not a dead motherboard scenario. Anyone has any ideas or faced similar situation? Please suggest.