How to access deceased fathers account

1

Try to use the steps provided on this link to recover your dad's Microsoft account.

https://support.microsoft.com/en-us/accounts-billing/manage/help-with-the-microsoft-account-recovery-form

2

If that is not possible, then accessing an account of a personal that has passed is basically a legal process that must be entered into, that information is provided on this link.

https://support.microsoft.com/en-us/accounts-billing/manage/accessing-outlook-com-onedrive-and-other-microsoft-services-when-someone-has-died

3

If you want to reset that device and are still unable to access your dad's account, you should be able to do that, but you would need to choose the option to keep nothing during the reset, which would result in loss of all data on your dad's user account on the PC.

Start your PC, just as Windows attempts to load (spinning dots), press and hold Power Button for 5 - 10 seconds to perform a Hard Shut Down

Do this twice

On the third start Windows will boot into the Recovery Environment and from there you can access System Repair, Safe Mode, Command Prompt... etc.

Go to Troubleshoot - Advanced Options - Reset this PC

Choose to keep nothing

Then start the Reset

4

If you are blocked from resetting Windows by an Administrator password, you will need to clean install Windows using a bootable Windows USB, which you can create on an empty 8GB USB flash drive using the Media Creation Tool, depending on whether it is Windows 10 or 11 installed on that device.

Windows 10:

https://www.microsoft.com/software-download/windows10

Windows 11:

https://www.microsoft.com/software-download/windows11