Restore the files you made when you backed up VPOP3 - do NOT restore anything in the VPOP3\pgsql folder tree
Restore the registry backup you made as well by double-clicking on the .REG file you made
Reinstall VPOP3 into the location where you restored VPOP3. This should reinstall the PostgreSQL database system. Do not start VPOP3 at this time
Open a command prompt, and go to the VPOP3 directory
If you are restoring the backup over an existing VPOP3 database (especially if the database files are damaged) you will need to DROP the database first. To do this, run pgsql\bin\dropdb -U postgres vpop3. When it prompts for the password enter the PostgreSQL master password - default pgsqlpass.
Run pgsql\bin\pg_restore -U postgres -d vpop3 DBBACK-<number>.DMP where <number> is the latest number of the database backup made by VPOP3. When it prompts for a password enter the PostgreSQL master password - default pgsqlpass