Go to "Services", find Postgres, and try a manual restart, see what
happens. Then check the recovery tab and see what it is supposed to do on
failures - you are probably at the "Do nothing" count limit, hence the no
auto restart.
If you can manually duplicate the failure to restart, try increasing the
logging, removing extensions, simplifying the postgresql.conf, etc, until
it starts working again. I suspect it will restart fine, though. Maybe
check anti-virus software logs?
Cheers,
Greg