VPOP3 version 3.x and later require a PostgreSQL installation to be able to work. For most users, the installer will automatically install PostgreSQL on the same PC as VPOP3 and configure it appropriately, but this article explains how to manually install and configure PostgreSQL for advanced users who may want install it differently (eg on a different PC or drive) or if you are having problems using the normal installer.
VPOP3 versions 3 or 4 require PostgreSQL 8.3 or later. VPOP3 version 5 requires PostgreSQL 9.1 or later. So, it may be best to install PostgreSQL 9.1 if you are installing manually, to avoid the need for a database server upgrade if you upgrade to VPOP3 version 5 later. (There are no known incompatibilities between VPOP3 versions 3-4 and PostgreSQL 9.1 - later versions of PostgreSQL may introduce incompatibilities)
Download the relevant version of PostgreSQL from http://www.enterprisedb.com/products-services-training/pgdownload#windows - note that VPOP3 will work with either the 32 or 64 bit versions of PostgreSQL, although the standard distribution distributes the 32 bit version. You can use whichever version you wish.
Once you have downloaded the installer run it
pgsqlpass, but obviously you may use any password you prefer. However, if you forget the password you may have big problems in the future, so make sure you do not forget it!
5432. We would recommend leaving it at that unless you have other software using that port on this computer (e.g. another PostgreSQL installation)
When the installation has finished, uncheck
Launch Stack Builder on Exit and Finish
Finally, you need to create a user and database for VPOP3 to use.
pgsqlpass) and press OK