The service was running fine, then I restarted the system and service was not starting. Force service restart says "service started and then stopped". In, Event Viewer, I found "pre existing memory block is still in use".
I have tried restarting the service after deleting postmaster.pid and posgresql.conf, as suggested at number of places, which I do not understand really. I have also tried reinstall PostgreSQL on previous data directory, that also does not work. Can you please help? Thanks Vinit Saini