Spike
> Is there an easy way to restore all the default settings of the server without losing any of the information on the drives?
signal-event post-upgrade
signal-event reboot
Doing the above may not fix your problem as the problem is still undiagnosed.
In server manager select View log files
and review the various files looking for clues, start with the messages log file
Also use the commands
top -i
and
htop
to see what processes are running and using up system resources