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
