Do you have another power supply to try, to rule that out?

You need to back up all your data for a conversion. It will remove all partitions and you’ll have to reinstall Windows and everything else.

https://learn.microsoft.com/en-us/windows-server/storage/disk-management/change-an-mbr-disk-into-a-gpt-disk

Can you log in as the local admin (adminstrator)? Do you not have the password?

Does the MB have any digital diagnostic codes on it?

Try running “Resource Monitor” and see if that helps in identify anything

There’s monitoring software such as

https://www.workexaminer.com/

older devices may not support WPA3, but if all your devices can use and connect with WPA3, then go with that for more security

Right click on the folder you are trying to share

Go the Sharing tab

Click on Advanced Sharing…

Make sure “Share this folder” is checked, then click on Permissions and make sure “Everyone” has full control

You should still have a password, the PIN just uses windows Hello feature

Have you tried “Reset this PC” through “Settings… Recovery”?

What OS is your server using?