When I start is beeps with green white and orange light

Hi!

Does the beeping has a pattern to it? Or is it just one beep and then it stops? Does your computer show any other signs of life, fans starting or anything else?

There are a few different lights on the Dell OptiPlex 9020, the diagnostic light is the amber light by the power supply. (See the power-supply diagnostic light in the overview manual)
The diagnostic pattern works in two stages:

• The amber diagnostic light starts flashing either two or three times.
• Then comes a pause.
• After the pause the light will flash up to seven times.
• Then the light will have a longer pause and then repeat indefinitely.

These flashing corresponds to the error codes. Please see the Dell OptiPlex 9020 Power Led Diagnostic guide for interpreting the error codes and for a more detailed description of how the diagnostic light works.
Now that you know how error codes work, please watch them carefully and then respond with which error code your computer is giving you.

If you have the error code 2, 3 (two flashes, pause, three flashes), than that would indicate "system board, memory or CPU failure" according to the manual.
If that is the case, then please remove and reinsert all of your components in the computer. See this manual for disassembly and assembly of your specific computer.

• Start by pulling out the ram sticks, and then put them back in again. Then try starting your computer.
• Then proceed to take out and reinsert all the power supply connections to your motherboard. Then try starting you computer.

If you have the error code 2, 3 and above did not solve your issue, then please respond and we'll see how we can further assist you.

Good luck

cheers