EDIT: 3020 micro is separated from 3020 desktop

http://downloads.dell.com/published/pages/optiplex-3020m-desktop.html#Manuals

https://topics-cdn.dell.com/pdf/optiplex-3020m-desktop_owners-manual_en-us.pdf

Drivers

http://downloads.dell.com/published/pages/optiplex-3020m-desktop.html

Deleting or Changing an Existing System and/or Setup Password

Ensure that the Password Status is Unlocked

(in the F2 System Setup) before attempting to delete or change
the existing System and/or Setup password.

You cannot delete or change an existing System or Setup
password, if the Password Status is Locked.

To enter the System Setup, press immediately after a power-on or reboot.
1.In the System BIOS or System Setup screen, select
System Security and press .
The System Security screen is displayed.
2.In the System Security screen, verify that Password Status is Unlocked.
3. Select System Password, alter or delete the existing system password and press or .
4.Select Setup Password, alter or delete the existing setup password and press or .

NOTE:
If you change the System and/or Setup password, re-enter the new password when
promoted. If you delete the System and/or Setup password, confirm the deletion when
promoted.
5.Press and a message prompts you to save the changes.
6.Press to save the changes and exit from the System Setup.
The computer reboots.

Disabling a System Password
The system's software security features include a system password and a setup password. The password jumper disables any password(s) currently in use.

NOTE:
You can also use the following steps to disable a forgotten password.
1.Follow the procedures in Before Working on Your Computer.
2.Remove the cover.
3.Identify the PSWD jumper on the system board.
4.Remove the PSWD jumper from the system board.
NOTE:The existing passwords are not disabled (erased) until the computer boots without the jumper.
5.Install the cover.

They are very hard to see.

Hi,

Please help where located jumper RTCRST for Optiplex 3020M (Micro)? And how to do it, my PC turn on but no display indicated bios corrupted. I will appreciate if send me step guide with pictures. Many thanks

You have incomplete crashed bios update.

You have killed the board.