Cannot start Postgres : invalid data in PID file

Problem: Cannot start Postgres
Platform: Postgres 8.3, Windows Vista Home
Error Message: pg_ctl: invalid data in PID file "C:/Program
Files/PostgreSQL/8.3/data/postmaster.pid"

I run postgres on Windows Vista Home Edition. It normally runs as a
service but is not starting. I created a command line instruction by
copying the data from Windows service GUI and changing "runservice" to
"start". Under the command line it produces the following:

C:\Users\Daron>"C:/Program Files/PostgreSQL/8.3/bin/pg_ctl.exe" start -N
"postgr
esql-8.3" -D "C:/Program Files/PostgreSQL/8.3/data" -w
pg_ctl: invalid data in PID file "C:/Program
Files/PostgreSQL/8.3/data/postmaste
r.pid"

Entering "type postmaster.pid" in the appropriate directory produces a
couple of blank lines.

I thought of trying to delete the PID file but I am not sure if it may
cause further problems.

Can anyone help?

Regards,
Daron.