bleh, looks like you might have to manually edit the registry to alter the executable path for a service
I'd hoped there was a gui option in the services manager to do this.
DO NOT DO THAT UNLESS YOU KNOW WHAT YOU ARE DOING. If you do know about registry editing, further instructions will not be necessary
It is probably much easier to start / stop postgresql manually, using the pg_ctl application provided for this purpose (you can see all the "service" does is execute a pg_ctl command, really)
open an administrator command prompt, refer to this document:
http://www.postgresql.org/docs/8.3/stat ... g-ctl.html - you are likely to need the -U option to specify the service should run as user postgres.
Good luck,
dave.