Postgres service is not starting

[Vinit Saini <vinits@xxxxxxxxxxxx>]

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