Many a time a device gets disabled with Device Manager Error Code 20 because the firmware of the device did not give it the required resources. This is a low-level hardware problem which will need access to the BIOS. The error message displayed is:

This device is disabled (Code 29)

To resolve this issue, first, make a note of the device name, and then restart your computer. Press DEL key or F12. This will take you to the BIOS. Now search for the devices list, and this device is in a disabled state. If yes, enable it.

In case it still doesn't work, you may have to check Manufacturers information about the device to see if there are special instruction given to configure it in the BIOS.