PostgreSQL Windows 7 support is a piece of dog sh#t. That is why you almost always have a loads of quirks on the table here and there. Beware that i’ve described Postgre installer in a soft words, it deserves way more. Original installer skips almost all things which should be done by a proper one: it won’t initialize your database it won’t kickstart windows service it won’t setup system environment with correct variables it f#cks up user roles it throws loads of errors in your face like Problem running post-install step.