You won't lose the database, if you reinstall PostgreSQL and it detects the old database.
Install 8.4.11 from
PostgreSQL: Welcome. (it will update the existing PostgreSQL installation and attempt to start the service again)
Turn on the secondary Logon. The secondary logon service is a standard windows service which is available on every windows computer. In the latest versions it is not started automatically. You need to start it via control panel > administrative tools > services. Starting it once should insure it works in the future also.
Check your hosts file:
http://holdemmanager.net/forum/showthread.php?t=8182