dell OptiPlex 9020 sff Power button no response.

Hi @noahfreak

Check if the RTC coin cell battery on the motherboard is OK and perform a power refresh at the same time.

Here's what to do:

Disconnect the power to the PSU and then open the desktop and remove the coin cell battery from the motherboard. (see bottom of p.24 of the owner manual)

When the battery is out, measure its voltage. If it is <2.5V DC or if it's >4-5 years old replace it. The battery is a CR2032 Lithium coin cell battery available most everywhere e.g. supermarkets. Check the battery type number on the battery to verify.

Before reinserting either the original coin cell battery (if its voltage is between 2.6V-3.0V) or a new replacement, press and hold the Power On button for a full 30 seconds and then release it.

This resets the BIOS back to its factory default condition in case corrupted data may be preventing a normal start.

Reinsert the coin cell battery and reassemble the desktop. Connect the power to the PSU and check if it turns on OK.

If it does there may be a message stating that the date and time are incorrect. This is normal as the BIOS has been reset. Once the date and time are corrected the message won't appear again when next starting the PC. Also any user definable BIOS settings that were altered by you to suit whatever operating requirements you needed, will have to be changed back as well.