I have just replace my motherboard on Optiplex GX 360 with a used working motherboard. After the board has been mounted in the case, I disconnected all the devices i.e the hard drive and the DVD drive. The board is powered up with a green steady light showing on the power button while diagnostic lights 2 and 3 also have steady green lights but 5's green light dims and brightens in response to the rising and falling speed of the processor cooling fan. No light at all on number 1, 4 and 6 diagnostic terminals. No beeps, no error message and no video or display on the screen.
This is the problem I am trying to solve which I am seeking assistance from the Community and the experts.