Question : Problem: Dell will not power up

I have a dell optiplex gx240. It will not power up. When I press the power button it blinks orange or amber color. No POST or any noise from the harddrive or any fans. I open the tower and the motherboard light is orange amber color. I tried with different power supplies and still no luck.

Answer : Problem: Dell will not power up

From here

http://support.dell.com/support/edocs/systems/opgx240/en/ug/problems.htm#1104867

Power Light Code - Solid yellow
      
Cause - A device on the system board may be faulty or is incorrectly installed.
      
Action - Be sure that each microprocessor is properly seated, remove all expansion cards, and then reboot. If the computer does not boot, see "Getting Help" for instructions on obtaining technical assistance.