Postgresql 11 – service doesn’t start

I use PG Admin 4 with PostgreSQL 11 for my data. After some kind of crash yesterday, I am not able to start postgresql anymore. I've done some research, but it doesn't look like a localhost, IP address, or port issue.

The log file states (in bold what I think is relevant):

2021-03-21 06:49:36.682 AEDT [11796] LOG:  database system was shut down at 2021-03-20 14:56:05 AEDT
2021-03-21 06:49:36.682 AEDT [11796] LOG:  invalid record length at 5B1/CA7F5900: wanted 24, got 0
2021-03-21 06:49:36.682 AEDT [11796] **LOG:  invalid primary checkpoint record**
2021-03-21 06:49:36.682 AEDT [11796] **PANIC:  could not locate a valid checkpoint record**
2021-03-21 06:49:36.890 AEDT [13136] LOG:  startup process (PID 11796) was terminated by exception 0xC0000409
2021-03-21 06:49:36.890 AEDT [13136] HINT:  See C include file "ntstatus.h" for a description of the hexadecimal value.
2021-03-21 06:49:36.890 AEDT [13136] LOG:  aborting startup due to startup process failure
2021-03-21 06:49:36.898 AEDT [13136] LOG:  database system is shut down

I have checked the postgresql.conf and pg_hba.conf files. They look fine and unchanged (allowing all users, having the right IP address, and port number).

postgresql.conf

# - Connection Settings -

listen_addresses = '*'      # what IP address(es) to listen on;
                    # comma-separated list of addresses;
                    # defaults to '*'; use '*' for all
                    # (change requires restart)
port = 5432             # (change requires restart)
max_connections = 100           # (change requires restart)
#superuser_reserved_connections = 3 # (change requires restart)
#unix_socket_directories = ''   # comma-separated list of directories
                    # (change requires restart)
#unix_socket_group = ''         # (change requires restart)
#unix_socket_permissions = 0777     # begin with 0 to use octal notation
                    # (change requires restart)
#bonjour = off              # advertise server via Bonjour
                    # (change requires restart)
#bonjour_name = ''          # defaults to the computer name
                    # (change requires restart)

# - TCP Keepalives -
# see "man 7 tcp" for details

#tcp_keepalives_idle = 0        # TCP_KEEPIDLE, in seconds;
                    # 0 selects the system default
#tcp_keepalives_interval = 0        # TCP_KEEPINTVL, in seconds;
                    # 0 selects the system default
#tcp_keepalives_count = 0       # TCP_KEEPCNT;
                    # 0 selects the system default

# - Authentication -

#authentication_timeout = 1min      # 1s-600s
#password_encryption = md5      # md5 or scram-sha-256
#db_user_namespace = off

**pg_hba.conf**
# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
# IPv6 local connections:
host    all             all             ::1/128                 md5

My SSD hard drive, which contains the data directory of postgres seems fine (i.e. I can read / write and access all files). In an effort to fix my starting issue, I was trying to run pg_resetwal but unsuccessful because the program did not open although the postgres service stopped.

From the Windows logs:

Waiting for server startup...
LOG:  listening on IPv6 address "::", port 5432
LOG:  listening on IPv4 address "0.0.0.0", port 5432
LOG:  redirecting log output to logging collector process
HINT:  Future log output will appear in directory "log".

pgAdmin gives me the following (obviouldy I can't start postgresql…):

could not connect to server: Connection refused (0x0000274D/10061) 
Is the server running on host "localhost" (127.0.0.1) and accepting TCP/IP 
connections on port 5432? 

Do you have any idea what could be wrong here? Many thanks!