replace cmos

I use sleep, shutdown via power and restart. I went to the fast start area and saw hibernate was not enabled at startup.

Hi,
Having hibernation off does not effect sleep it just won't hibernate or hybrid sleep which you may already know if it was already off :)

I always unplug the PC when maintaining the inside of the PC. Otherwise there is still a +5V standby supply to the motherboard and you risk shorting something if you drop the battery or a screwdriver onto the motherboard.

You need to record the BIOS settings you are using, particularly for settings like secure boot. I store these settings in a file and keep a printed copy with my motherboard user guide. Some people take screen photos but this is somewhat laborious. Check to see if your BIOS can save BIOS settings and save them if possible.

When removing the CMOS battery, check the open circuit voltage is good between 3.0-3.4V. I replace any battery under 2.9V. Restart the PC, enter the BIOS and set the BIOS defaults. Restart the PC again, enter the BIOS and load your user BIOS settings from file if you were able to save them. Else you will need to enter the settings manually from the notes you made or photos taken.