First of all, make sure that your motherboard truly has a TPM 2.0 chip. This component is usually present on most machines, but if yours is truly an old one, it might not. Below is a small procedure to help with this process:

To start the Run dialog, press the Windows + R keys, type tpm.msc, and hit OK.

This should open the Trusted Platform Module (TPM) Management console.

In the TPM Manufacturer Information screen, check the value of the Specification Version. This should be equal to 2.0, as in the screenshot below.

Those that are not seeing this console screen and receive an error instead of the Compatible TPM is not found, then the TPM chip is not available on your motherboard or is actually disabled in BIOS.

You will have to turn the TPM state chip to ON, directly from BIOS.